Discerning the Meaning of Ties in a Complex Network: Personal Lending in Early Renaissance Florence

This paper presents work done jointly with Neha Gondal.  We use the structure of a particular social network as a clue for discerning the different meanings given to a single type of tie by different actors.  Our argument is based on analysis of a network of 3,590 personal loans involving over 2,200 persons in Renaissance Florence.  Specifically, we argue that different local patterns of lending within the network as a whole suggest that the act of lending was construed differently by different groups of Florentines interacting with each other. These differences seem to have arisen from the way ostensibly similar persons were differentially exposed to disparate contexts, including different exogenous network domains, within a world comprised of multiple networks.  We derive hypotheses about the various possible meanings of lending from archival sources and from current historiography.  We demonstrate that loans circulated through a strong component within the complete network, while lending outside the strong component was sparser, unreciprocated, and frequently conducted within family, in accordance with traditional mores about lending.  Ties within the strong component were embedded in more complex structures of reciprocation, cyclicity, and transitivity, and actors located there participated significantly more frequently in the world of business and public administration.  Thus one part of Florentine lending was traditional, and another part commercialized.  Membership in either of these subnetworks was more determined by outside experiences than by fixed social attributes like social class, neighborhood, or blood.  A mixed Exponential Random Graph Model demonstrates the importance of both structural configurations and actor attributes for understanding the organizing principles of this lending "market."