This article uses the renowned antiquarian Nicolas-Claude Fabri de Peiresc (1580-1637) as a case study to examine the intellectual and religious culture of the early seventeenth century. In particular, using his extensive correspondence, it investigates the manner in which the exchange of letters could be used to reinforce the identity of one confession (Catholicism), while at the same time facilitating dialogue between individuals of different confessions, faiths and cultures. It also examines the extent to which material gifts and hospitality, offered regardless of the recipient's faith, served to reinforce such relationships in the emerging Republic of Letters.