The division between the Latin and Greek churches is one of the fields of research that best represents the complexity and richness of the medieval world and opens the way to a deeper understanding of contemporary religious and political issues. This volume, planned as a journey from the ninth to the fifteenth century and through three different linguistic areas (Greek, Latin and Slavic languages), contains twenty-five contributions ranging from large images of the main points of difference between churches (e.g. papal primacy and Filioque) to new editions of texts (e.g. Letter by John Dokeianos to John Moschos). The new analyzes proposed by this volume portray a lively community of well-known and young scholars who are radically changing the history of the Schism between Orthodox and Catholic Churches through new discoveries and revaluations of texts and events.