Anglo-Saxon Computus Manuscripts
Because Easter must fall on a Sunday, but its lunar terminus a quo
(luna XIV) can fall on any weekday, the age of the moon on Easter can vary between 15 and 22: cf. the rota of Easter termini on fol. 5v. In consequence, all observations tied to Easter, such as Lent, Maundy Thursday, or Pentecost, will also fall within a seven-day span of the lunar month. This table is a concordance of the lunar dates for Quadragesima Sunday ("Initium", i.e. of Lent), mid-Lent, "C<oena> ap<ostolorum>" or Maundy Thursday, Easter, the octave of Easter, Ascension, and Pentecost. Somewhat similar tables appear on fol. 32r and fol. 34r, but they are not common outside MS 17: the sole comparandum located to date is in the
fol. 48v (42) which has an additional column for "Moysicum Paschae."