In 325 AD The First Council of Nicaea was convened by Emperor Constantine the Great
Constantine the Great decided after having a vision that Christianity was true
and changed Roman law allowing Christianity to be worshipped.
result of the council was also the begining of what we know now as the Roman Catholic Church they brought in Easter.
“We also send you the good news of the settlement concerning the holy pasch or (passover), namely that in answer to your
prayers this question also has been resolved. All the brethren in the East who have hitherto followed the Jewish practice
(observing the passover) will henceforth observe the custom of the Romans and of yourselves and of all of us who from
ancient times have kept Easter together with you.”