This is a Biblical fact. We celebrate the resurrection of Our Lord ...NOT the Jewish sabbath. We ceased being Jews sort of by mutual consent way back in Acts of the Apostles, which I guess will make the allegation true that the Catholic Church did indeed change the Lord's Day...since the Christians in the early church WERE Catholics... and THEY did change it...
Mark 16 :2 And very early in the morning, the first day of the week, they come to the sepulchre, the sun being now risen.
Mark 16 :9 But he rising early the first day of the week, appeared first to Mary Magdalen, out of whom he had cast seven devils.
Luke 24 :1 And on the first day of the week, very early in the morning, they came to the sepulchre, bringing the spices which they had prepared.
John 20 :1 And on the first day of the week, Mary Magdalen cometh early, when it was yet dark, unto the sepulchre; and she saw the stone taken away from the sepulchre.
Acts Of Apostles 20 :7 And on the first day of the week, when we were assembled to break bread, Paul discoursed with them, being to depart on the morrow: and he continued his speech until midnight.
1 Corinthians 16 :2 On the first day of the week let every one of you put apart with himself, laying up what it shall well please him; that when I come, the collections be not then to be made.
Pax vobiscum,