Protestant Letter Networksregulatory networks, and social networks-share an underlying order and follow simple laws, and therefore can be analyzed using the same mathematical tools and models.2 These publications build on work from various different disciplines, such as sociology, mathematics, and physics, which stretches back some decades. The theoretical approaches of social network analysis have already made an impact in the fields of historical corpus linguistics, coterie studies, and the history of science, amongst others; but the application of mathematical and computational techniques developed by scientists working in the field of complex networks to the arts and humanities is a relatively recent development, and one that is gaining increasing traction, offering as it does both technical tools and a sense of contemporaneity in a world now dominated by social networking platforms. despite these developments, however, there is still much work to be done before these statistical methods are embedded within the literary historian's toolbox. all too often the word "network" is used by scholars in this field as a useful metaphor-in much the way that Thomas More wielded the word "canker." This article will demonstrate how the mathematical tools employed by network scientists offer valuable ways of understanding the development of underground religious communities in the sixteenth century, as well as providing different approaches for historians and literary scholars working in archives.while it is not possible to corroborate More's fears about the extent and organization of evangelical communities in england during the 1530s due to lack of documentation, considerable evidence for the structure of the underground Protestant communities functioning in the catholic reign of Mary i survives in collections of correspondence. early modern correspondence provides a unique textual witness to social relations and structures. gary schneider has described renaissance letters as "sociotexts": as "crucial material bearers of social connection, instruments by which social ties were initiated, negotiated, and consolidated." 3 Letters were the method by which people sought patronage, garnered favor, and engineered their social mobility; they were a means of communicating alliance, fidelity, and homage; and they could be used "as testimonies, as material evidence of social connectedness."4 The modern perception of private correspondence was one that simply did not exist in the early modern period. instead, epistolary conventions implicated multiple parties in the composition, transmission, and reception of letters. common letters (intended for more than one recipient or written by more than one sender) most clearly demarcate the idea of an epistolary community, but senders also