This article examines the formulation and circulation of Eastern Christian knowledge on eitherside of the Mediterranean, especially on the basis of Catholic missionary archives and academic pro-ductions, the study of which is sometimes rooted in non-Anglophone academic traditions. The aim isto shed light on how knowledge relating to Eastern Christianity was assimilated in Europe, as well asthe role missions played in this process, especially from the last third of the nineteenth century,when the institutions and instruments for the circulation of knowledge emerged.2This new knowl-edge was largely based onfieldwork conducted in the Middle East, particularly on manuscripts con-served in the monasteries, churches, congregational centres, missionary societies and patriarchates,and more generally in the literary, linguistic, archaeological, and cartographic heritage of Christiancommunities living there. Another objective is to address the circulations and transformations ofthis knowledge on either side of the Mediterranean: collected and developed in major Europeanlibraries and universities, it was integrated by the governance structures of churches, but quiteoften also returned to the space it originated from, where it was reappropriated and gave rise topatrimonial processes, notably alongside the sometimes tragic experiences of certain communitiesduring the end of the Ottoman Empire and the establishment of new states.