Rome took up this idea in the first and second centuries (AD) and then the Germanic peoples took the 7-day week but assigned new names for some to fit with their own gods. English has derived its week day names chiefly from this source.
Sun-day known as 'the first day of the week' by the Jews (Matt 28.1; Mk 16.2,9; Lu 24.1; Jn 20.1,19; 1 Cor 16.1,2), became known after the Resurrection as the Lord's Day (Acts 20.7; Rev 1.10).
Of course, Sabbatarianism disputes the fact that sun-day has become the Lord's Day claiming that the Roman Pope changed the day from the seventh day to the first day. Although the Roman church claims that the papacy has existed continuously since St Peter it is clear that even if that were the case, the Bishop of Rome's office changed markedly between the first century and later centuries where the titles and power of the pope increased in grandeur (e.g., vicar of Christ title).
However, the Didache (a teaching manual of early Christianity c. AD 50-160) directs that Christians meet together on 'the Lord's Day'. Other early church fathers (pseudo-Barnabas, Justin Martyr, Irenaeus, and Tertullian) also testify that the first day of the week is the Lord's Day and deserving of respect because Jesus Christ was resurrected on that day.
It was be a good thing if Christians reclaimed this day within their own circles by again calling it The Lord's Day as many other Christians have done throughout the centuries. The almost universal use of the word 'sun-day' for the first day is further evidence of the power of the secular mindset in Australian society.
As to those Christ-believers who keep the Jewish Sabbath (Seventh-Day Adventists, Messianic Jews), I have no particular quarrel as long as they grant to Lord's Day observers the same freedom of conscience as I am happy to extend to them.
