Trading Firm of the Soranzo Brothers ( 1406-1434 ) and Its Commercial Network

Over the last few decades the range of research strategies available to historians has been considerably broadened thanks to the adoption of methods employed in other branches of science. These include but are not limited to the methodology of social network analysis (SNA), which has been developed by sociologists since mid1950s and is based on the concept of social structure as a system of ties linking various social actors.1 When applied to economic history, such an approach means shifting the focus of attention from individual economic entities, i.e., households, companies, banks, governments, etc., to the relationships existing between them.2 The relevance of network analysis to this research field has been convincingly demonstrated in a number of studies drawing upon material from diverse chronological periods, geographical areas, and cultural settings.3 Recent publications by Francisco Apellániz,4 Andrea Caracausi,5 Stefania Montemezzo,6 and other scholars7 attest to the idea that the use of such methodology can be particularly appro-

es in the principal European centers of trade, 13 the Venetian men of affairs adhered to more flexible organizational practices. Many of them were individual merchants relying on a complex web of commission agents, factors, and other intermediaries to conduct their operations. 14 The word compa(g)nia (company) referred in the Venetian context to a joint venture, i.e., a short-term business association created in order to carry out a single project or undertaking, for instance, a commercial voyage. Given that a collaborative enterprise was usually liquidated at the end of this project, the arrangement normally lasted no more than a few years. 15 The niche of a more permanent business entity was occupied by a fraterna (from the Latin frater -"brother"), or a family partnership comprising brothers who retained joint ownership of hereditary property after their father's death. The sons of the late pater familias became members of such partnership by default unless they initiated the division procedure, therefore fraterna constituted not only the most common form of business organization in the Republic but also one of the basic units of the Venetian society. 16 The social and economic functions performed by the family of this particular type were inextricable, and its internal structure mirrored that of the patriciate itself insofar as the brothers possessed equal shares of patrimony and had equal powers to administer joint property. The dynamic interaction between individual merchants, family partnerships, and short-term companies lay at the heart of the Venetian economy, 17 enabling it to swiftly adapt both to the changing market conditions and to the shifts in the political situation. At the same time, the complexity and the fluidity of the resulting system impede the application of traditional historical methods in its study and suggest that the economic structure of the Venetian Republic would be more adequately interpreted in terms of network approach. 13 R. DE 17 Ibid., pp. 52-54.

LIMITATIONS OF NETWORK ANALYSIS IN MEDIEVAL STUDIES. WHOLE-NETWORK APPROACH VS EGOCENTRIC APPROACH
As is often the case with research tools imported from other fields of science, the use of network analysis in medieval history encounters some limitations. First and foremost, this methodology sets high requirements for the quality of data used, meaning that the latter has to be accurate, relevant, consistent, and complete. 18 Unfortunately, historic material surviving from the Middle Ages rarely meets the completeness criterion, which is considered vital by network specialists. As Bonnie H. Erickson rightfully noted, the loss of 10% of information would not necessarily be critical in a research employing traditional historical methods but would have a dramatic impact on the results of a network study if some of the unaccounted ties were of great structural importance. 19 Due to the damage done by time and chance to primary sources, the medievalists usually deal with more or less representative natural samples, which inevitably leave out certain actors and relationships. In order for the history of Middle Ages to benefit from network analysis and the opportunities it offers, this circumstance needs to be temporarily set aside by implicit agreement between scholars.
However, apart from trying to reconstruct a whole network, there is also another strategy available to researchers. While in medieval studies it is rarely possible to gather data on the entire web of actors and their relationships, many types of primary sources allow a historian to explore so-called "egocentric", or "ego-centered", networks, which represent ties connecting a specified central actor, also referred to as "ego" or "focal subject", with various individuals and entities denoted by the term "alters." 20 A basic "first-order" or "1-degree" network of this kind comprises a central node (i.e., the ego), a number of other vertices (alters), and edges linking the former with these latter, but it can expand so as to include ties between different alters of the same ego or even all of the alters' connections, becoming a "1.5-level" or a "second-level" network, respectively. 21 The most obvious limitation of the egocentric approach is that it depends upon the experience of a particular focal subject and therefore offers a deeply personalized view of network structure. 22 Nevertheless, the scope of this method can be broadened by merging multiple egocentric networks and comparing their 18  properties, as is commonly done in modern sociology, where the networks of this type are studied with the help of surveys and questionnaires, 23 and the focal subjects are sampled from large segments of population. 24 In theory, collecting and processing egocentric data on every member of the group may ultimately lead to reconstructing the whole network since the latter consists of actors who are surrounded by their own egocentric networks, and thus the two network designs turn out to be interdependent and interrelated. 25 At the same time, with respect to the economic history of the late Middle Ages, the examination of stand-alone egocentric networks also appears worthwhile, especially if the lacunae in primary sources prevent one from taking a broader approach. To indicate just a few of its potentialities, this method permits to summarize heterogeneous data on the relations of a certain economic entity, be it a household, a firm, a bank, or even a government; to represent such material visually in a comprehensible form; to explore the structure of the resulting business network and its properties, such as size, density, or composition; and finally, to conduct the attribute analysis of individual ties, ranking them by their strength in order to reveal the "core" of the ego's closest connections.

PRIMARY SOURCES ON THE SORANZO TRADING FIRM
The present study aims to contribute to the larger body of research on the Venetian commercial networks by examining the system of business relationships maintained by the Soranzo fraterna, a family partnership that operated during the first half of the 15th century and comprised brothers Donado, Giacomo (Iacomo), Piero, and Lorenzo Soranzo, sons of the late miser Vettor Soranzo of the San Samuele parish (contrada San Samuel). The activity of this trading firm is documented in its two surviving account books, which are commonly referred to as the libro real vechio and the libro real novo (or the libro reale vecchio and the libro reale nuovo in the Italianized spelling), and which are currently kept in the custody of the State Archives of Venice, 26 along with some commercial letters pertaining to the Soranzo brothers and their business partners. 27 Being the smaller of the two ledgers, the libro real vechio contains 51 leaves and has at least 16 missing, if one is to rely upon the original numeration; the entries in this book cover the period from 1410 to 1416. The manuscript of the libro real novo, which consists of 168 filled folios bearing dates from 1406 to 1434, is fully preserved and well-known to both accounting and economic historians. The attention on the part of the former is warranted by the fact that this ledger is generally considered the earliest extant Venetian example of double-entry bookkeeping and is mentioned as such in most treatises on accounting history. 28 With regard to the study of late medieval economy, the libro real novo provides a breadth of information on the flow of goods, the volume of trade, price movements, profit rates, various types of costs, etc., all of this data having enormous value for the researchers since the period it refers to is rather poor in the number of accounting sources surviving in Venice. Given that the Soranzo brothers had specialized in the import of raw cotton from Syria, their ledger has been cited not only by scholars exploring the Levantine trade in general 29 but especially by those who have been interested in this particular branch of commerce, like Wolfgang von Stromer 30 and Jong-Kuk Nam. 31 The latter, for instance, has relied upon the libro real novo to demonstrate how the community of South German merchants residing at the Fondaco dei Tedeschi had functioned as the main outlet for cotton supplied from Syria and Egypt, and has identified many of the fraterna's German customers and the localities of their origin. 32 Despite frequent mentions of the presently discussed account books in various pieces of research, modern historiography lacks a comprehensive study of the Soranzo firm and its business activity, which is largely due to the irregular (or  anomalous, in the words of Reinhold C. Mueller 33 ) nature of the libro real novo. The more extensive of the two surviving Soranzo ledgers was not used to record the everyday facts of economic life but compiled from a number of accounting sources, including the libro real vechio, in order to be presented at the Venetian court of the giudici di petizion. Although this conclusion had been first explicitly stated by Tommaso Zerbi in 1952, 34 the exact circumstances behind the creation of the manuscript remained unknown until the author of this paper was fortunate enough to discover four judicial decisions, or sentences (sentenze a giustizia), 35 pronounced by the giudici di petizion in the case of Vettor Soranzo, son of the late Donado, against his uncles Giacomo, Piero, and Lorenzo Soranzo. As it appears from these rulings, the controversy that lasted at least from 1429 to 1445 and brought about the compilation of the libro real novo originated when Vettor claimed full restitution of his mother's dowry and other funds belonging to his father in proprio or in specialità ("on his own behalf"), along with the profits gained from the investment of said funds in the commercial operations of the family partnership. In the course of the ensuing litigation, the parties to the trial and the court-appointed arbiters hired no less than two accountants, each of whom was tasked with preparing a so-called "extrato" or "estratto" (lit. "extract, excerpt"), i.e., a kind of expert opinion providing estimate of settlement due to the plaintiff. The libro real novo can be identified with one of these extrati, meaning that the accounts copied into the ledger were selected specifically for court purposes and are likely to misrepresent the financial result of operations conducted by the fraterna in the litigants' interests. 36 However, there is no doubt that the materials included in the book were retrieved by a forensic accountant from authentic financial documents and ledgers, therefore the deficiencies of the libro real novo do not impede using it to recreate the egocentric network of the Soranzo firm. In future, the network reconstructed with the help of this compilation may be inserted with additional information from the commercial letters of the Soranzo brothers and from the accounts of their agent Lorenzo Priuli, 37 and thus the scale of potential omissions and distortions suggested by the nature of the libro real novo may finally be revealed. 33

Extracting Tie Data
The data on the business relationships of the Soranzo fraterna is contained in nearly every entry of the libro real novo, but it can be most conveniently retrieved from the personal accounts, where it is presented in a systematic manner. It is worth mentioning here that, according to modern classifications, the term "personal account" refers to any account opened in the name of a certain individual, a business entity, or a public institution. 38 From a total of 1097 accounts existing in the Soranzo ledger, 39 713 or 65% fall into this category, and only 384 (35%) are impersonal. In view of the objectives set in the present study, the author chose not to include into analysis the accounts of various officials and magistrates of the Venetian Republic, such as the Chamera da imprestedi, 40 the Provededori dele blave, 41 the extraordinarii, 42 and others (25 accounts altogether), those of religious and charitable organizations (11 accounts), as well as 43 bank accounts. Another group that has to be treated separately consists of three fraterna accounts, 43 an account entitled "Heirs of miser Vettor Soranzo" ("Chomessaria de miser Vettor Soranzo"), 44 32 accounts opened in the names of brothers comprising the family partnership, i.e., Donado,45 Giacomo, 46 Piero, 47 and Lorenzo Soranzo, 48 and two accounts of Vettor di Donado Soranzo. 49 While some of these were employed to register deals concluded by a certain member of the fraterna, 50 others are somewhat reminiscent of the modern capital and drawings account and were most likely created by an expert responsible for compiling the libro real novo in connection with the judicial proceedings. 51 The remaining 596 personal accounts relate to individual men of affairs, family partnerships, or companies of merchants, and their holders constitute actors in the business network of the Soranzo fraterna. Interestingly, the average number of entries made in these accounts is only 3.8, or about 1. 86 82%) two, and 15 one entry, the total number of accounts with less than four entries equaling 409 or 68.62%. Though 32 accounts of this type contain more than 10 entries each, and the longest of them consists of 43 entries, overall the bookkeeping practices of the Soranzo fraterna display a tendency for a personal account to record operations involved in completing a single business transaction (i.e., a sale, a purchase, etc.). Such pattern seems to fit into the description given to the Venetian accounting system by Frederic C. Lane, who coined the term "venture accounting" to stress out the fact that the 15 th -century Venetian merchants had not balanced their books at regular intervals, like Florentines had, but had established the results of each business enterprise separately. 52 For instance, the Soranzo brothers opened a special account for every overseas venture and for every lot of merchandise imported from the Levant. The debit of a merchandise account 53 contained all of the costs incurred in connection with a particular consignment, while the credit stated the amount and the contract value of the merchandise purchased by customers. It was only after the whole lot had been sold and the bookkeeper had received complete information on expenses that such an account was closed into the profit and loss account. Each entry in the credit of the merchandise account required a corresponding entry to be made in the debit of a buyer's account. 54 Thus, the debit column of the customer's personal account conveyed how much he owed to the fraterna, and the credit recorded the sums he paid. Once the payments received by the Soranzo brothers totaled the contract value of merchandise sold, the customer's personal account was closed; if the holder failed to meet his obligations, the balance of his account was transferred to the account of bad debts ("Debitori chattivi"). 55 The same principles applied to the management of other personal accounts, with the obvious exception that, in the accounts for trade payables, the roles were switched, so the credit column stated contractual obligations undertaken by the Soranzo brothers, and the debit reflected the discharging of their liabilities.
The small average number of entries in the 596 personal accounts of the libro real novo has several implications for network research. First of all, the practice of using particular accounts to register a single business transaction makes it easier to group them by the kind of operations reported, and this procedure in turn opens the way for classifying the account holders according to the functional type of tie linking them to the Soranzo fraterna, i.e., according to one of the key attributes of a business relationship. 596 personal accounts from the libro real novo can be divided into about 21 categories based on the entries' content, and though some of these groups consist of only one or two accounts, their number testifies to the variety of deals contracted by the Soranzo merchants. By far the largest category contains 333 accounts of customers who bought some merchandise from the fraterna, the turnover of these sales being as high as 8414.731 lire di grossi or approximately 84147 ducats. In contrast, there are only 56 accounts opened in the names of suppliers, the total of purchases registered in them barely amounting to 1131.587 lire di grossi, which is less than, for instance, the sum of private loans obtained and provided by the Soranzo merchants, according to 43 accounts of their lenders and borrowers (1191.976 lire di grossi). The huge gap between the two most numerous groups of personal accounts does not convey the actual difference between the contract values of goods acquired and sold by the firm, as one might have expected. The discrepancy is due to the fact that the commodities offered by the fraterna at the Venetian market had mostly been imported from the Levant, therefore the costs of procuring them were entered in the account of a person responsible for a particular commercial venture, or voyage (viazo), be it a commission agent or one of the Soranzo brothers themselves. 56 Since the firm's overseas suppliers interacted with its main office through representatives and not directly, the libro real novo contains no personal accounts opened in the names of these oriental men of affairs and in general provides very little information on their identities and their relationship with the fraterna, making it impossible to include them in the egocentric network reconstructed on the basis of this ledger. To obtain more complete data on the firm's ties to Levantine traders, one would have to consult the accounts which the Soranzo brothers and their commission agents kept while residing abroad, and all of these materials except for the aforesaid records of Lorenzo Priuli (1409-1413) 57 seem to have either got lost or perished.
Apart from sales, purchases, and loans, personal accounts from the libro real novo report other less common types of business dealings, including, but not limited to, transactions performed under a commission agency contract (26 accounts) or under a joint enterprise agreement (6 acc.), operations with government bonds (16 acc.) and bills of exchange (12 acc.), barter deals (9 acc.), will execution (6 acc.), rendering of services (6 acc.), rental payments (4 acc.), and disbursement of dowry (2 acc.). Of particular interest are 46 accounts that each record two or more different types of transactions and thus do not conform to the general tendency for the personal accounts to register a single deal. A few of these heterogeneous accounts were retained perpetually or at least kept for prolonged periods of time, running up to dozens of entries, which is likely to indicate the existence of a stronger and more permanent connection than a purely business relationship. In fact, among the hold- 56 For examples, see: Ibid., ff. 65s, 69s. 57 ASVE, Miscellanea di carte non appartenenti ad alcun archivio, 8. ers of such accounts one finds Luca di Leonardo Donado, 58 who married Marcolina Soranzo, the sister of the four Soranzo brothers, and brothers Niccolò and Giacomo Priuli, 59 sons of Costantino and the cognadi (in-law relatives) of Donado Soranzo. While it is evident that the ties between these actors and the fraterna had a complex, multifaceted nature, the network approach in itself does not allow to determine which aspect of their relationship served as the driving force in creating and maintaining the linkage. In other words, it is unclear whether the pre-existing social and familial ties led to frequent economic interactions with a number of individuals, or the firm's business interests prompted the Soranzo merchants to seek certain matrimonial alliances. Solving this problem would require both the use of additional primary sources and the application of other research methods besides network analysis.

Reconstructing the first-order business network
In order to reconstruct the 1-degree network of the Soranzo merchants, the author integrated the contents of 596 personal accounts found in the libro real novo into a tabular database where each entry corresponded to a linkage between the fraterna and a certain actor, i.e., an account holder. This procedure entailed identifying partners with more than one account opened in their names and pooling information relating to them so as to obtain weighted data on the alters' attributes. The resulting first-order egocentric network, which is visually represented in Figure 1.1, 60 consists of 469 ties, the average number of personal accounts per holder being about 1.27. The abundance of overlapping vertices and edges makes this graph hardly readable, so the weak, insignificant, or occasional connections have to be filtered out to achieve a more meaningful and comprehensible visualization (refer to Fig. 1.2 for example). The set of attributes that characterize each of the ties forming the network includes those identifying the alters, such as the name of a counterparty, his or her city of origin, ethnicity, parentage (if known), and the style of address employed, and those describing the relationship itself, i.e., the duration of contact with the fraterna, the functional type of tie, the number of personal accounts an actor had in the libro real novo and whether or not they were balanced, the number and the volume of transactions recorded in these accounts, and the chosen form of payment. 58 ASVE, Miscellanea Gregolin, 14, Libro real novo, ff. 80s, 83d, 89d, 109s, 123d, 151d, 165d ("Ser Lucha Donado"). 59 Ibid., ff. 100s, 123s ("Ser Nichollo e Iachomo di Priolli"). 60 The network graphs in Figures 1.1 and 1.2   While all of the above-listed attributes can be employed to analyze the composition and the structure of the Soranzo egocentric network, the one that is especially relevant with regard to the broader problem of economic integration between various regions of Europe and the Mediterranean in the Middle ages is the actors' provenance. Since the accounting records of deals concluded between the firm and foreign merchants are capable of revealing trade flows connecting Venice with other centers of commerce and production, the historians have long attached great value to this kind of data, whether or not their research has been networkoriented. For instance, Jong-Kuk Nam has studied the geographical distribution of the fraterna's customers with special emphasis on the German buyers of cotton, drawing up a table where these latter were grouped by their provenance and plotting the clients' cities of origin on a map. 61 The adoption of network approach 61 J.-K. NAM, Le commerce du coton en Méditerranée, cit., pp. 388-391. provides opportunities for a deeper examination of this material, starting with its quantitative analysis, which finds itself considerably facilitated and encouraged within this methodological framework. In the particular case of the Soranzo fraterna, creating the database of the personal account holders has enabled the author not only to tabulate the geographical distribution of alters in the egocentric network but also to compute the number of accounts and accounting entries, as well as the approximate turnover of operations, for each of the groups united by common origin (see Table 1 in the Appendix and Figures 2.1, 2.2 below).

Fig. 2.2. Turnover of personal accounts in the libro real novo by the origin of their holders (detailed breakdown; in lire di grossi, approx.)
Obviously, the values presented in Table 1 are of approximate nature due to some limitations of the libro real novo as a historical source, and first of all to the fact that the individuals mentioned in the ledger are not always easily identifiable; for example, a number of variant spellings are usually found for foreign surnames and toponyms, and same person is occasionally referred to in several different ways. Furthermore, since only 195 account holders out of 469 (41.58%) have their provenance explicitly stated, the author has taken upon herself to single out the members of well-known Venetian families 62 and to include 41 actors with German-sounding names into the category "Germans of unknown origin", along with 4 people who are designated in the manuscript as "todeschi" or "d'Alemagna". Although one cannot altogether avoid the risk of erroneous identifications, which would have resulted in some minor database inaccuracies, the general picture is rather clear, revealing the preponderance of German customers in the Soranzo trading network and the prominent position of merchants from Ulm, Nuremberg, and Augsburg within this group of foreigners. At the same time, the average number of accounting entries per person is much higher for Venetians than it is for Germans (6.74 versus 4.02, respectively), which can be interpreted in the sense that the Soranzo brothers interacted with their fellow compatriots on a more regular basis.
In addition to its rich potential for the quantitative analysis of attribute data, the network approach permits one to evaluate the relative importance of actors and to rank them within the system of relationships. With respect to the Soranzo case, the most obvious criteria for assessing the strength of tie connecting an alter to the ego are the frequency of mutual interactions and the volume of operations. The first parameter is indirectly reflected by the number of personal accounts and entries contained in them, while the second can be measured with the approximate turnover 63 of the said accounts. The 5% of actors who rank highest according to these criteria and thus form the core of the Soranzo business network are listed in Table 2 (see Appendix). The above-mentioned Luca Donado holds the top spot in all three groups, making it hardly surprising that in the late 1420s the giudici di petizion appointed him one of the arbiters in the litigation between Vettor di Donado Soranzo and his uncles. 64 Other actors present in every column include Giacomo di Antonio Dandolo, 65 70 Venetian moneychanger Donado di Fellipo, 71 and even one woman -Agnesina Venier, 72 widow of Andrea, who named the Soranzo brothers executors of her will.
However, apart from the purely quantitative criteria cited in Table 2, ties within the Soranzo business network can also be assessed with respect to the nature of transactions carried out by the actors. The classification of partners according to the functional type of their relationship with the fraterna (see Table 3 in the Appendix) takes as a point of departure the content-based classification of personal accounts (see section 4.1 of the present paper). Since both rely on the type of business deals registered in the libro real novo as a criterion for forming groups, the actors fall into categories that essentially reiterate those of personal accounts and include, for example, customers who acquired merchandise from the fraterna (256 actors), the firm's suppliers (45 actors), commission agents (19 actors), lenders and borrowers (26 actors), investors partaking in operations with government bonds (15 ac-tors), service providers (6 actors), parties to bills of exchange (9 actors) and to barter deals (4 actors), joint enterprise partners (1 actor), et al. However, personal accounts opened in the name of the same person sometimes belong to two or more different content-based groups, revealing the heterogeneous character of operations conducted by the individual in question. Holders of such accounts make up the category of actors with multifunctional ties to the fraterna, along with partners possessing personal accounts of the mixed type.
Unsurprisingly, the group of 61 alters who interacted with the Soranzo merchants in several various capacities features some members of their inner social circle and extended family, including relatives by blood (for example, uncles Tommaso Soranzo 73 and Vido da Canal, 74 cousins Stefano di Niccolò Contarini 75 and Bartolomeo di Tommaso Soranzo) 76 and by marriage (i.e., the already mentioned Luca Donado, Giacomo Dandolo, and brothers Giovanni, Niccolò, and Giacomo Priuli). At times the individual's exact relation to the fraterna may remain unknown, but the nature of the transactions themselves implies social connection, as is the case with Agnesina Venier, whose will the Soranzo brothers executed, or with the unnamed prioress 77 of the San Lorenzo convent, where their sister Fontana 78 took the veil. At least 17 actors with multifaceted ties to the fraterna were foreigners, 12 of them Germans and 5 Italians, and while these men of affairs occupy a prominent place in the group, the business activities they engaged in appear significantly less diversified than those of the firm's Venetian partners. Like most of their compatriots, these foreigners generally bought articles of Levantine import (14 actors), the main difference being that, in addition, they also sold to the fraterna (3 actors) or bartered (10 actors) merchandise of their own. Less common for the members of this subgroup was to use various financial instruments, such as bill of exchange (lettera di cambio, 2 actors), guarantee (proferta, 2 actors), or loans (1 actor).
As for the remaining 31 partners who were linked to the fraterna with multifunctional ties but are not known to be related to the Soranzo brothers by blood or by marriage, their provenance is not indicated in the account books, therefore it is likely that the majority of them were Venetian citizens (cives de intus or de extra) or patricians. Their dealings with the firm demonstrate highly diversified and individualized combinations of business activities and operations, making it hard to detect patterns of economic behavior; the same applies to members of the Soranzo clan but not to the subcategory of foreigners. A cursory assessment of the subgroup constituted by the Venetians with multifaceted ties to the fraterna reveals the presence of actors involved in the day-to-day running of the Soranzo household, such as Dario Zusto, 79 the proprietor of storage facilities rented by the firm, Niccolò da Verseia, 80 fameio of Donado Soranzo, and a bunch of local artisans and shopkeepers (Carlo Coldiera, 81 owner of a botega; Renaldo, sartor a Rialto; 82 choltrer Andrea da Lorssa; 83 drapieri Luca and Francesco Zivran; 84 miedego Graziadio). 85 Two members of the group performed the duties of official brokers, or sanseri, at the Fondaco dei Tedeschi, and this circumstance merits special attention since the law required the state-appointed intermediaries of trade to participate in every deal concluded with German merchants and worth more than 10 ducats. 86 Throughout the many years of their business career, the Soranzo brothers interacted with dozens of sanseri, the fees due to these latter having been regularly entered into the merchandise accounts, along with other expenses, 87 but only Bortolamio Alivoto 88 and Iacomo Perazo 89 had personal accounts in the libro real novo. Their particular closeness to the fraterna suggests the potential for illicit agreements not unlike those described by Philippe Braunstein in his recent book. 90 The central position held within the network by the actors with multifunctional ties to the ego finds reasonable explanation in the fact that concluding several deals of various types with a certain counterparty generally bespeaks coincidence of financial interests, mutual trust, and possibly even a social connection. However, a strong business relationship, though perhaps lacking meaningful social implications, can also emerge thanks to the recurring economic transactions of the same kind. For this reason, a comprehensive analysis of the Soranzo trading network would have to take into consideration the above-listed homogeneous categories of account holders (see Table 3 in the Appendix), especially the largest group comprising 256 buyers of goods. A brief survey of actors who engaged the firm exclusively to acquire merchandise shows that the absolute majority of clients (182, or 71.09%) made only one purchase, so they had no chance to form any sort of lasting connection with the Soranzo brothers. Nevertheless, the fraterna did gain some regular customers, and 14 buyers (5.47%), most of them Germans, concluded more than three deals each, the turnover of sales reported in their personal accounts amounting to 2156.807 lire di grossi, as opposed to 3155.659 lire di grossi spent by 182 onetime buyers. Hence it follows that though the Soranzo firm had access to a rather large and depersonalized distribution network, the ultimate success of its business strategy depended heavily on a small number of wholesale merchants strongly connected to the fraterna.

CONCLUSION
The network analysis initiated by the author in this study leaves plenty of room for the application of more specialized and sophisticated research procedures, as well as for the deeper interpretation of its results. At the present stage, the Soranzo business network comprises only actors of first order, i.e., those directly linked to the fraterna, and only those with personal accounts opened in their names. Its scope can be further broadened by adding bankers and individuals who did not possess their own accounts in the libro real novo but played important structural roles in the organization of commerce, like brokers and intermediaries of trade (sanseri), patrons of ships, or other actors mentioned in the entries recording overhead and transportation costs of merchandise. Nevertheless, the egocentric network reconstructed hitherto allows some new light to be shed on the patterns of economic interactions in the business circles of late medieval Venice. Since the data on the relationships maintained by the Soranzo trading firm ("the ego") with its partners ("alters") came from the accounting records, every known tie within the network manifested itself in the value of goods or the sum of money that had changed hands, and thus it possessed an inherent quantitative dimension. This has enabled the author to assess the strength of linkages by the number and the volume of transactions conducted with a given individual and to rank the actors accordingly, highlighting those who had invested most heavily in their dealings with the Soranzo merchants.
In addition to the quantitative criteria, the relationships within the network were also classified according to their functional types, which had been defined by the nature of deals concluded. This procedure brought into view the diversity of economic transactions performed by the firm and their mostly impersonal character, at the same time revealing the core of partners with strong multifaceted ties to the Soranzo fraterna. The composition of this group turns out to be remarkable in several ways. For one thing, it demonstrates the priority of relationships formed through marriage over those predetermined by kinship patterns. While in recent historiography it has been suggested that the acquisition of political and social advantages through matrimonial alliances may not have been a widespread phenomenon in late medieval Venice, 91 the account books of the Soranzo fraterna provide one with vivid examples of the day-to-day economic cooperation between the in-laws who interacted much more tightly than blood relatives or members of the extended Soranzo clan. Furthermore, the core of the Soranzo network contains high percentage of foreigners, mostly South German merchants residing at the Fondaco dei Tedeschi, which results from the fact that the family partnership invested the bulk of its capital in cotton trade. On the other hand, the regular and prolonged business contacts with a group of Germans acting as bridges to the rest of the community may have led to the emergence of permanent social linkages, and these latter may have, in their turn, prevented the fraterna from trying to broaden its specialization in order to adapt to the changing market conditions and to the shifts in the political situation. In this manner, the case study of the Soranzo trading network ultimately contributes to revealing both the organizational patterns of the Venetian trade in the Eastern Mediterranean and the underlying mechanisms of economic integration between the Venetian Republic, the Levant, and the cities of Southern Germany.