"Acceptance of Easter over Passover did not come without resistance. Two religious leaders of the mid-second century—Polycarp, bishop of Smyrna; and Anicetus, bishop of Rome—debated this very point.
Anicetus argued for Easter while Polycarp, stated Encyclopaedia Britannica, defended observing "the Christian Passover, on the 14th of Nisan, the first month of the Jewish ecclesiastical calendar, regardless of the day of the week" (15th edition, Micropaedia, Vol. VIII, p. 94, "Polycarp").
Polycarp taught observance of the Passover as the early Church had observed it. Eusebius said Polycarp did so because this was the way "he had always observed it with John the disciple of our Lord, and the rest of the apostles, with whom he associated" (Eusebius' Ecclesiastical History, 1995, pp. 210-211). These Christians of the second century were still following the example of Jesus Christ (1 Corinthians 11:1; 1 Peter 2:21; 1 John 2:6) in observing the Passover.
Several decades later another leader, Polycrates, argued with Victor, bishop of Rome, over the same issue. Eusebius wrote of the continuing debate:
"There was a considerable discussion raised about this time, in consequence of a difference of opinion respecting the observance of the paschal [Passover] season. The churches of all Asia, guided by a remoter tradition [biblical truth preceded Roman confusion], supposed that they ought to keep the fourteenth day of the moon for the festival of the Saviour's passover, in which day the Jews were commanded to kill the paschal lamb ...
"The bishops ... of Asia, persevering in observing the custom handed down to them from their fathers, were headed by Polycrates. He, indeed, had also set forth the tradition handed down to them, in a letter which he addressed to Victor and the church of Rome. 'We,' said he, 'therefore, observe the genuine day; neither adding thereto nor taking therefrom. For in Asia great lights have fallen asleep, which shall rise again the day of the Lord's appearing, in which he will come with glory from heaven, and will raise up all the saints ...
"Moreover, John, who rested upon the bosom of our Lord; ... also Polycarp of Smyrna, both bishop and martyr. Thraseas, ... Sagaris, ... Papirius; and Melito ... All these observed the fourteenth day of the passover according to the gospel, deviating in no respect, but following the rule of faith. Moreover, I, Polycrates, who am the least of all of you, according to the tradition of my relatives, some of whom I have followed. For there were seven, my relatives [who were] bishops, and I am the eighth; and my relatives always observed the day when the people (i.e., the Jews) threw away the leaven.
"I, therefore, brethren, am now sixty-five years in the Lord, who having conferred with the brethren throughout the world, and having studied the whole of the sacred Scriptures, am not at all alarmed at those things with which I am threatened, to intimidate me. For they who are greater than I, have said, 'we ought to obey God rather than men'" (Eusebius, pp. 207-209)."
Easter: Masking a Biblical Truth