 Calculating the proper date of Easter ("computus") then became a complicated process involving a lunisolar calendar, finding the first Sunday after an idealized Passover on the first full moon after the equinox.Various tables were drawn up, aiming to produce the necessary alignment between the solar year and the phases of the calendrical moon.The less exact 8-year cycle was replaced by (or by the time of) Augustalis's treatise "On the measurement of Easter", which includes an 84-year cycle based on Meton.