The Seventh-Day Adventists claim that Christians celebrated the same seventh-day Sabbath as the Jews, until forced to change by Emperor Constantine (why is always Constantine? the anti-trinitarians blame him, too). While I have addressed the biblical refutation of that claim before (such as here), this time I want to address the historical evidence.
One of the earliest Church Fathers was Ignatius of Antioch, the first bishop of that city, who was a disciple of the Apostle John, and testifies to the practices of the church in the immediate post-Apostolic period. In his Epistle to the Magnesians 9:1, he says, ""If, then, those who had lived according to
ancient practices came to the newness of hope, no longer keeping the [Jewish]
Sabbath, but living in accordance with the Lord's Day, on which our life
also rose through Him and His death (which some deny), the mystery
through which we came to believe, and because of which we patiently
endure, in order that we may be found to be disciples of Jesus Christ,
our only teacher." He is describing the historical practice of what Paul advises in Colossians 2:16: "So don't let anyone condemn you for what you eat or drink, or for not
celebrating certain holy days or new moon ceremonies or Sabbaths." Notice the list of things that Paul lists, all of which were elements of the Jewish ceremonial law, and, therefore, abrogated as completed in the cross work of Christ. That is, Paul is not dismissing the Sabbath, per se. Who would he be to dismiss one of the Ten Commandments? Rather, he is disputing against the Jewish ceremony of Sabbath.
Ignatius describes the carrying out of that exhortation, with the replacement of the seventh-day Jewish Sabbath, with the Christian Sabbath, the first day of the week, because it was the Lord's day, the day of His resurrection and the completion of our redemption! Thus, the Christian Sabbath became the practice of the Christian Church, as described by Acts 20:7 and I Corinthians 16:2, almost three hundred years before the time of Constantine.