The 'Cultural variety in the Christian Orient: Christian Arabic language and literature in the Middle Ages' (Cocallma) project partners applied the neo-Lachmannian form of literary criticism to the manuscript, and carefully analysed its written language. The text has been written in middle or mixed Arabic, which was used in the Medieval period by the Orthodox Arabic Melkite Church. Project activities have concentrated on the retrieval and collation of manuscripts and the identification of the author's sources. Research missions have been carried out by project partners, including a study of the Christian Arabic texts held at the National Library of France, in Paris. The result has been the identification and study of a new source, which contained fragments of the famous Muslim encyclopaedic collection known as 'The epistles of the Brethren of Purity'. This has been a significant discovery as it reveals similarities between the Bishop of Gaza's work and the Epistles, rendering it possible that al-Gazzi was familiar with the Brethren of Purity. Later studies have revealed, however, that the main source has been the 'Book of demonstration' by the 12th century Arab mathematician Abu Bakr al-Hassar. This book, together with the theological writings of Theodore Abu Qurra and John of Damascus, has influenced Palestinian Christian literature produced in the Middle Ages. A new edition of the Sulayman ibn Hasan al-Gazzi's work will enable better understanding of Palestinian theological thought during the Fatimid era. Furthermore, it will help to reveal how the circulation of literary texts in the premodern Arabic world was not restricted by religion. Oriental Christianity is a promising field of research which helps us to understand how knowledge has been transferred from the East to the West and to consider the centuries-old cohabitation between Christians and Muslims in the Middle East. This information is highly relevant as it enables a more informed understanding of the current political and religious challenges facing Europe.