It is not clear at all. As Eusebius makes clear, it wasn't just the "Roman" church. Only the Johannines in Asia Minor were Quartodeciman; the whole rest of the world was on Sunday.
And my question to Diego stands, if this was such an apostate practice, why did the Johannines not *refuse* Communion with the Roman Church? If Easter Sunday is apostasy, then the disciples of John were gladly keeping company with apostates.
Do you know something they do not?
You know....I don't think the early Church, once it came to understand the mission, wanted to excommunicate anyone. I think that developed later as a "Scare Tactic", but not in the Churches of the East.
There is nothing Biblical....or Christian about Easter. On the other hand, Passover is Biblical....being celebrated in both Testaments.....by the people of God.
That's the whole point. The original church of God celebrated a Christian Passover on Nisan 14 according to God's commandment and the example of Christ. Shortly thereafter, corruption began to creep in. I don't know what form of relations took forth between the two but the issue itself caused a HUGE (or HUGH in freepspeak) controversy that it still talked about and studied to this day. Those who apostasized would have done well to heed Paul's advice:
2Th 2:7 For the mystery of lawlessness is already at work; only he who now restrains will do so until he is taken out of the way.
2Th 2:15 Therefore, brethren, stand fast, and hold the traditions which ye have been taught, whether by word, or our epistle.