Up until the creation of the modern day christian church, the early congregation continued to hold the original Sabbath(Shabbat) on the seventh day which is from Friday(roman calendar) at dusk until Saturday(roman calendar) at dusk. Even the Messiah and His taught ones(disciples) never deviated from the actual Sabbath. The change came from the Holy Roman Catholic Church, created by constantine, at the council of laodicea in 364. Not only did they change the day of the week that the Sabbath(Shabbat) occured on, but they also modified the original command so that rest was optional and not mandatory. The wording states that it is in order to break away and not be like the Jews, but there is too much evidence on other subjects which points to the Holy Roman Catholic Church as blending paganism into Christianity.
http://reluctant-messenger.com/council-of-laodicea.htm
(anathema means "cursed")