Easter date set in 325 A.D.

"Council of Nicaea in AD 325, the issue was finally settled by the church as a whole. The desire of

the churches as a whole, even prior to the council, was to unite the entire body of Christ on this all-important day of celebrating the Resurrection...Though we do not have the records of the discussions that framed the debate, copies of letters sent to absent bishops still exist. It seems that one of the major issues of contention was that the celebration of the Jewish Passover had slipped to a period before the vernal (spring) equinox. Thus, the council determined the date should be fixed to the first Sunday following the full moon after the vernal equinox.

In light of the agreement by the council, a letter distributed to the synods of the Church of Alexandria stated:

We further proclaim to you the good news of the agreement concerning the holy Easter, that this particular also has through your prayers been rightly settled; so that all our brethren in the East who formerly followed the custom of the Jews are henceforth to celebrate the said most sacred feast of Easter at the same time with the Romans...

 Constantine provided a rationale for his desire to set a common Sunday date.

When the question relative to the sacred festival of Easter arose, it was universally thought that it would be convenient that all should keep the feast on one day; for what could be more beautiful and more desirable, than to see this festival, through which we receive the hope of immortality, celebrated by all with one accord, and in the same manner? It was declared to be particularly unworthy for this, the holiest of all festivals, to follow the custom [the calculation] of the Jews, who had soiled their hands with the most fearful of crimes, and whose minds were blinded. . . . We ought not, therefore, to have anything in common with the Jews, for the Savior has shown us another way. . . . As, on the one hand, it is our duty not to have anything in common with the murderers of our Lord...

 Disputes remained about which astronomical cycle would be used and on which day the equinox fell. The Romans held to March 21 while the Alexandrians set the date as March 18. Also, some churches would not celebrate on the Sunday following the full moon. Though minor disputes continued, the dates for Easter from the Roman Church were set in tables followed by a majority of churches." AIG
....but rather resolve this, not to put a stumbling block or a cause to fall in our brother’s way. Romans 14:13