This holiday is celebrated in the spring by the Jews. The church, which believe that the resurrection took place on a Sunday. The council of Nicaea determined that Easter should always fall on the first Sunday after the first full moon, following the vernal equinox. In consequence, Easter remained without a fixed date but proximate to the full moon, which coincided with the start of Passover on the 15th of the Hebrew month Nissan.
Easter
Christians call this holiday the holy day because of Christ resurrection. Easter, which celebrates Jesus Christ’s resurrection from the dead, is Christianity’s most important holiday. Instead, Christian churches in the West celebrate Easter on the first Sunday following the full moon after the vernal equinox on March 21. Therefore, Easter is observed anywhere between March 22 and April 25 every year. Orthodox Christians use the Julian calendar to calculate when Easter will occur and typically celebrate the holiday a week or two after the Western churches, which follow the Gregorian calendar.
Schorsch, Rabbi Ismar. "Passover and Easter." My Jewish Learning. N.p., n.d. Web. 12 Apr. 2017.