Coptic Months in Islamic Years. The use of the fiscal year (al-sana al-ḫarāǧiyya) in Fatimid Egypt (969-1171 CE) against the background of Arabicisation and Islamisation

This study investigates the combination of Coptic months on the one hand, and years that refer to the chronology of Islam on the other, especially in the so-called fiscal (ḫarāǧ) year, in documentary and narrative sources from Egypt, with a focus on Copto-Arabic historiography. The main research question is that of the correlation between the choice of calendar (Coptic, fiscal, Islamic) and religious identity (Christian, Muslim). After a discussion on the problem of a lunisolar year in early Islamic Egypt, some documentary texts (Arabic papyri) from the first three centuries following the Arab conquest are analysed. The rest of the paper concentrates on the Fatimid period (969-1171 CE), when the ḫarāǧ year was given an official status. Again, the confessional prosopography in documentary texts is compared to the choice of system for naming months and counting years. The final section investigates the calendars used in a selected part of the Arabic History of the Patriarchs of Alexandria, the official history of the Coptic Church.