In the early modern period, conversionary institutions were established in Rome, Paris, and London for drawing the Muslims and the ‘oriental’ Christians of the Ottoman Empire to the Catholic and the Protestant churches. In the past quarter of a century, large numbers of studies have focused on the efforts and methods of the missionaries, without examining the resistance that was expressed by Muslims and eastern Christians. Furthermore, the emphasis has been nearly exclusively on European sources. This paper (part of a book project on “Religious Conversion in the Euro-Arab Mediterranean, 1517-1798”) focuses on Arabic manuscripts, written by two Arabic speakers, a Muslim captive and an Orthodox priest, that describe resistance to conversion. They are first-hand accounts that show the strategies that were adopted in confronting Catholic missionary effort. The first set of manuscripts is preserved at the Franciscan Library in Valletta and consists of writings by a North African Muslim captive in the early seventeenth century. He was given the task of transcribing Arabic Christian material but then subverted the content by adding his own critical comments. The second set is at the Bibliothèque Orientale in Beirut’s Jesuit University and consists of letters by an eighteenth-century priest from the patriarchate of Antioch in Syria describing the French-backed Catholic missionaries’ disruptive attempts to win over his congregation. These manuscripts are unique in that they show resistance to conversion, couched in expressions of fear and anxiety, not in the translated language/s of the missionaries, but in the native Arabic idiom.