On the new edition of Grosseteste’s Compotus

The medieval ecclesiastical calendar rested on the foundation of two interlocking calendrical cycles, which were represented by the Julian calendar, with its 28-year cycle of weekdays, and by a 19-year cycle of ‘epacts’ for tracking the phases of the Moon. Monks and clerics who sought to learn more about the scientific background of these cycles, or simply to familiarize themselves with their use, could do so by turning to books Continue reading