The 8‐Year Cycle and the Invention of the Epacts

Alden A. Mosshammer

in The Easter Computus and the Origins of the Christian Era

Published in print October 2008 | ISBN: 9780199543120
Published online January 2009 | e-ISBN: 9780191720062 | DOI:

Series: Oxford Early Christian Studies

The 8‐Year Cycle and the Invention of the Epacts

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Eusebius attributes to Dionysius of Alexandria (249–65) both the earliest known assertion of a rule that Easter can be observed only after the equinox and the use of an eight‐year cycle (octaeteris) for Paschal calculations. The Coptic tradition, however, remembers Demetrius of Alexandria (189–232) as ‘the inventor of the epacts’ and Ethiopic texts attribute to him a Paschal computus beginning in AD 214. The earliest extant Paschal cycle is a 112‐year period attributed to Hippolytus, beginning with the full moon of 13 April in AD 222. The cycle of Hippolytus is based on the octaëteris and probably represents the adaptation of the cycle of Demetrius to the Roman calendar. Another 112‐year cycle is extant, composed in 243, but beginning with the full moon of 1 April in the year 242. Its authorship and provenance are unknown.

Keywords: Dionysius of Alexandria; Demetrius of Alexandria; eight‐year cycle; octaëteris; Hippolytus; 112‐year cycle; computist of 243

Chapter.  9898 words. 

Subjects: Christianity

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