Abstract: The Register of the Patriarchate of Constantinople, which contains more than 800 documents of the period 1315-1402, is one of the most important sources for the (church) history of this time of renewed Muslim expansion at Byzantiumʼs cost. First, this paper analyses how Islam is being described in these documents in regard to the terminology and the framework of traditional Byzantine polemics; besides more general terms such as “barbarians”, “infidels” or “enemies”, also more specific appellations with regard to religion (“Ismaelitai”, “Musulmanoi”) or ethnicity (“Persians”, “Turks”) are used in the Register. Second, the reaction of the Byzantine laymen but also of the lower and high clerics to the Islamic expansion as documented in the Register of the Patriarchate is surveyed: a main concern of the Patriarchate was the conversion of Christians living in areas under Muslim rule to Islam, a phenomenon which can be observed in several documents.

In contrast, we find very few examples of Muslims converting to (Orthodox) Christianity during this period. In partibus infidelium, the Byzantine church had to come to arrangements with the new potentates in order to receive permission to minister its flock; but the Patriarchate attempted to define limits for the collaboration between its hierarchs and Muslim rulers, which were, however, sometimes violated by bishops “on-site”. Some hierarchs were even prepared to acknowledge Muslim potentates as their legitimate secular overlords similar to the Byzantine emperor, forestalling the later agreement between the Orthodox Church and the Ottoman Sultan after the fall of Constantinople in 1453. Thus, the documents from the Register of the Patriarchate illustrate several cases of actual encounter between Byzantine Christianity and Islam in the 14th century besides the famous Byzantine works of anti-Islamic polemic (by John VI Kantakuzenos or Manuel II Palaiologos) of this period.

Keywords: Byzantium, Medieval Islam, Orthodox Christianity, Christianity and Islam, Medieval Turkish History, Late Byzantine History.

Biography author: Johannes Preiser-Kapeller (born 1977) received his doctoral degree in Byzantine Studies from the University of Vienna in 2006 and is researcher at the Institute for Byzantine Studies of the Austrian Academy of Sciences. His research includes studies on Byzantine foreign policy, especially towards early medieval Armenia (contributor to the “Regesten der Oströmischen Kaiserurkunden” for the period 565-867 AD, 2009), on the Byzantine Church (monograph “Der Episkopat im späten Byzanz”, 2008) and on the implementation of methods from modern social, political and complexity sciences into the study of the medieval Eastern Mediterranean (studies on network analysis and socio-historical dynamics).

Affiliations: Mag. Dr. Johannes Preiser-Kapeller, Institute for Byzantine Studies, Austrian Academy of Sciences, Vienna - Austria.

Preiser-Kapeller, Johannes (2011), 'Conversion, Collaboration and Confrontation: Islam in the Register of the Patriarchate of Constantinople (14th Century)', in: International Review of Turkish Studies, Winter 2011, Volume: 1, Issue: 4, pages: 62-79.