A on the calculation of the date of Easter attributed to DEMETRIUS I, twelfth of Alexandria (189- 231). We shall examine the attribution in light of the historical, liturgical, and literary Arabic traditions of the Middle Ages.

Historical Tradition

The historian Sa‘id IBN AL-BITRIQ, Melchite of Alexandria (933-940), tells us in his History, “At this period, Demetrius, the of Alexandria, wrote to Agapius, bishop of Jerusalem, to Maximus, patriarch of Antioch, and to Victor, patriarch of Rome, concerning the calculation of the Easter of Christians and their fast, [so as to know] how to calculate them from the Passover of the Jews. Numerous books and epistles were composed on this subject, until the Easter of Christians was fixed, as is done today.” According to A. Harnack (1893, Vol. 1, p. 330), this letter was written in the year 202.

Strangely enough SAWIRUS IBN AL-MUQAFFA‘ makes no mention of this letter in his History of the Patriarchs. However, the Copts’ Arabic SYNAXARION, composed at the beginning of the thirteenth century, mentions it twice, on 12 Babah and 10 Hatur. For 12 Babah we read, This day also, there fell asleep in the Lord . . . Demetrius, the twelfth of the city of Alexandria. This saint was an illiterate peasant who did not know how to write. He was filled with heavenly grace. He was acquainted with numerous sciences, knew the ecclesiastical books by heart with their commentaries, and spoke on many subjects and sciences. It is he who ordered the calculation of epact and that of the fast, and sent an epistle to each of the leaders of Rome, Antioch, Ephesus, and Jerusalem. When they were informed of this, they gave their approval and established it as a rule, keeping it effective until our days.

The entry for 10 Hatur reads: When Demetrius was made patriarch, he was a peasant who knew neither writing nor books. God illuminated his intellect by divine grace . . . and he composed the calculation of epact whereby the fast and the Resurrection are worked out. He composed it in Coptic and Greek and then sent a copy to our Father Victor, pope of Rome, one to our Father Maximos, of Antioch, and one to our Father Agapios in Jerusalem. When his letter reached the three sees, our Father Victor, pope of Rome, judged what was sent to him to be excellent, and it caused him great joy. He summoned fourteen learned bishops from dioceses of his jurisdiction and a number of wise priests. He read the calculation to them; they approved it, accepted it, and made a large number of copies of it which they sent to the other episcopal sees. Holy Lent and the glorious Easter were instituted as they are today.

Liturgical Tradition

The following Salam (peace) is sung in the Coptic liturgy on the feast of Saint Demetrius:

Hail to Demetrius, who ordered from drink, and organized fasting from foods for the fifty days!

Had this not been under the inspiration of the Spirit who reveals, how could it have been possible to discover and find the computation of the periods of time called epact.

Hail to you, o priests, be thanked and praised for having come with diligence and without delay to the meetingplace of the assembly where the calculation of epact dictated by the Holy Spirit was communicated to you by the venerable Demetrius.

Hail, o Demetrius, to your hands that wrote the computation of past epacts and that of future epacts.

Literary Tradition

In his history of Arabic Christian literature, G. Graf mentions no work attributed to Demetrius, of Alexandria, despite the fact he had already mentioned two of his works in his of the Christian of Cairo. Consultation of the manuscripts gives the following results.

Demetrius is attributed authorship of a work entitled Hisab al- Abuqti, (Calculation of the Epact), described as “a on chronology, with tables for the finding of Easter and other ecclesiastical festivals and commemorations,” and for the Passover of the Jews. This text is as yet unpublished, but it was translated into English by George Sohby from a manuscript in his personal possession. In actual fact, Demetrius’ name appears only toward the end.

There are at least three manuscripts of this text, in Birmingham ( Christian Arabic 11, dated 1599); in the Coptic Patriarchate, Cairo (History 60, eighteenth century); and in the George Sohby Collection, Cairo (1768). The Birmingham manuscript is mentioned in Graf’s Geschichte der christlichen arabischen Literatur (Vol. 4, p. 159).

In 1634 the anonymous owner of a fine manuscript of the Book of Epact of al-As‘ad ibn al-‘Assal dated 8 July 1354 (Vatican Library, Arabic 152) wrote in a long gloss on folio 123v that at Dayr al-Baramus there was a manuscript entitled Kitab al-Fadil (The Remainder) of the Book of Epact composed by the Demetrius of Alexandria. This may or may not be the same book as the one discussed here.

The Book of Epact was translated from Arabic into Ethiopian at an unknown date. M. Chaine writes, “We sometimes find attributed to Demetrius a of computation known as Bahr Hasab. This work is explicitly attributed to him in the British Museum manuscript Or. 815.” He mentions ten or so Ethiopian manuscripts of the same text that do not credit Demetrius and explains, “The name Bahr Hasab means “The Ocean of Computation.’ It is the translation of an Arabic title which has become the title to designate any composition dealing with the calculation of chronology” (Chaine, 1925, p. 26, n. 3).

At the Syrian Catholic Patriarchate of Sharfah, Lebanon, there is a manuscript (Arabic 13/36) copied by the Copt Barsum al- Manfaluti in 1422 (or maybe in 1522) from a manuscript of the priest Ghubriyal copied at the time of IV (1348- 1363). This manuscript contains a entitled Sharh Karmah wada‘aha . . . Anba Dimitriyus (cf. Armalah, pp. 461-62; Samir, 1976, pp. 344-45). This may be the Hisab al-Abuqti under a different title. Graf appears not to mention this manuscript in Geschichte der christlichen arabischen Literatur.

In a manuscript in the Coptic Patriarchate, Cairo (Theology 230), there is a brief text entitled “Corollary concerning the blessed New Year: the day of the year on which it occurs” (fols. 93b-94b). This may be an extract from the Hisab al-Abuqti. This text is mentioned in Graf (Vol. 1, p. 354, no. 8), under the name of Demetrius, of Antioch, whereas the manuscript attributes it to Demetrius of Alexandria.


  • Armalah, I. des manuscrits de Charfet. Jounieh, 1936- 1937.
  • Chaine, M. La chronologie des temps chrétiens de l’Egypte et de l’Ethiopie. Paris, 1925.
  • Graf, G. de manuscrits arabes chrétiens consérves au Caire. Studi e Testi 34. Vatican City, 1934.
  • Harnack, A. Geschichte der altchristlichen Literatur bis Eusebius, 2 vols. in 4. Leipzig, 1893-1904.
  • Samir, K. “ que l’on sait de la “Medicina moeroris et curatio doloris’ de Sawirus Ibn al-Muqaffa‘ (Xe siècle).” Le Muséon 89 (1976):339-52.
  • Sobhy, G. “The Coptic Calendrical Computation and the System of Epacts known as Hisab al-Abuqti “the Epact Computation’ ascribed to Abba Demetrius the XIIth Patriarch.” Bulletin de la Sociéte d’archéologie Copte 7 (1941):169-99. A translation without any analysis.