Christ was crucified as the Jews gathered in Jerusalem for the feast of Passover, so Easter's timing depended on the Jewish lunar calendar based on the 29H-day cycle from new moon to new moon.
(the Jews; gathered; L:in Jerusalem; for the feast of Passover) (the Jewish lunar calendar; based; on the 29H-day cycle from new moon to new moon)
the Jews the Jewish lunar calendar
gathered based
L:in Jerusalem for the feast of Passover
on the 29H-day cycle from new moon to new moon