<P> The Hebrew Sabbath, the seventh day of the week, is often spoken of loosely as "Saturday". In fact, in the Hebrew calendar, a day begins at sunset, and not at midnight . The Sabbath therefore coincides with what the Gregorian calendar identifies as Friday sunset to Saturday sunset . Similarly, the first day of the week ("Sunday") coincides with Gregorian Saturday sunset to Sunday sunset . The Sabbath continued to be observed on the seventh day in the early Christian church . To this day, the Sabbath continues to be observed in line with the Hebrew Sabbath timing in the church calendars in Eastern Orthodoxy and Oriental Orthodoxy . </P> <P> On the other hand, the current canons of the Roman Catholic Church (Canon 202 § 1) define a day as beginning at midnight . </P> <P> Early Christians continued to pray and rest on the seventh day . By the 2nd century AD some Christians also observed Sunday, the day of the week on which Jesus had risen from the dead and on which the Holy Spirit had come to the apostles . Paul and the Christians of Troas, for example, gathered on Sunday "to break bread," Soon Christians were observing only Sunday and not the Sabbath . Patristic writings attest that by the second century, it had become commonplace to celebrate the Eucharist in a corporate day of worship on the first day . A Church Father, Eusebius, stated that for Christians, "the sabbath had been transferred to Sunday". </P> <P> In his noteworthy book From Sabbath to Sunday, Adventist theologian Samuele Bacchiocchi contended that the transition from the Saturday Sabbath to Sunday in the early Christian church was due to pagan and political factors, and the decline of standards for the Sabbath day . </P>

When did the day of worship changed from saturday to sunday