Two Letters of Severus Sebokht on Easter Computation (665 AD)

Two previously unedited letters by Severus Sebokht, preserved in MS Paris, BnF, Syr. 346, document technical debates about astronomical methods for Easter computation. Written in 665 AD to Basil, a Syriac priest in Cyprus, these letters respond to disputes about calculating the Paschal full moon. Severus develops several aspects of the astronomical cycles underlying these calculations, drawing on Theon of Alexandria's work and other authorities, and includes his own Paschal table comparing Greek and Syriac astronomical calculations.