<P> Computus ( Latin for `` computation '' ) is a calculation that determines the calendar date of Easter . Because the date is based on a calendar - dependent equinox rather than the astronomical one , there are differences between calculations done according to the Julian calendar and the modern Gregorian calendar . The name has been used for this procedure since the early Middle Ages , as it was considered the most important computation of the age . </P>
<P> Computus ( Latin for `` computation '' ) is a calculation that determines the calendar date of Easter . Because the date is based on a calendar - dependent equinox rather than the astronomical one , there are differences between calculations done according to the Julian calendar and the modern Gregorian calendar . The name has been used for this procedure since the early Middle Ages , as it was considered the most important computation of the age . </P>
what determines the date for easter each year
what determines the date for easter each year
Computus
Computus