Despite centuries of Ottoman domination of Southeastern Europe and the division between Eastern Orthodox and Western Christianity, East and West were never completely and hermetically separated. There were always individuals from both regions who crossed religious, linguistic, cultural, political, and geographical borders, initiating numerous fruitful contacts and collaborations. This occurred particularly within the context of the so-called "Republic of Letters" (16th-18th centuries), which should not be confined to Western Europe as it has been in most related literature to date, but rather expanded to include Eastern and Southeastern Europe, including the Greek Orthodox world under Ottoman rule. Indeed, many Greek Orthodox individuals studied at Western European universities, translated various works (theological, philosophical, scientific, etc.) into Greek, and maintained regular correspondence with Western European scholars. Undoubtedly, these relations were asymmetrical at that time, given that the Western Republic of Letters had long been established and enjoyed prominent intellectual and social status. However, the potential contribution of the Greek Orthodox actors to such an exchange should not be underestimated, as they could provide their Western counterparts with valuable information, such as support in linguistic matters and access to sources inaccessible to the West. At the same time, tensions and conflictual interactions were not uncommon between these Eastern and Western actors due to past tensions, persisting confessional boundaries, and the role of the respective ecclesiastical establishments. Nevertheless, many of these actors aspired to rapprochement between the Christian worlds across the entire continent. In this session, we will evaluate this period of East-West interactions as a whole, based on selective cases, and set the agenda for future research in this fascinating area of East-West relations, which remains relevant to this day.