Computus

An elaborate bundle of techniques called computus therefore developed around Easter calculations. Computus formed the centerpiece of “scientific” education in the monasteries.

Source: wiktionary

Bede's work, which remained in active use for half a millennium, stood at the very center of the university curriculum, because the mastery of computus included many different essential subjects such as astronomy, mathematics, geography, theology, and law; its applications, too, included medicine and agriculture.

Source: wiktionary

The technical problems faced by Western computists when it came to dating the day of Christ's Passion and the year of the world's creation were so persistent and perplexing that only a radical solution could restore the lost coherence of computus and chronography.

Source: wiktionary

1987, Bruce Eastwood, 5: Plinian astronomical diagrams in the early Middle Ages, Edward Grant, John Emery Murdoch, Mathematics and Its Applications to Science and Natural Philosophy in the Middle Ages, page 149, This computus also contains only one completed Plinian diagram, that for the planetary harmonic intervals.

Source: wiktionary