Who invented Sunday worship? The Lord would have you worship him on Sunday, also on Monday, Tuesday, Wednesday, Thursday, Friday, and Saturday. He asked that you rest on the 7th day (Saturday). Rest from 7th day to the 1st day was changed by a law from Constantine and further by the Pope.
The Church of that day, then followed suit, and legislated on Sunday worship at the Council of Laodicea.
"The Council of Laodicea ... forbids Christians from judaizing and resting on the Sabbath day, preferring the Lord's day, and so far as possible resting as Christians."
Encyclopaedia Britannica, 1899 Edition, Vol. XXIII, page 654.
Here is the first Sunday Law decree of a Christian council. It was given about 16 years after Constantine's first Sunday Law of A.D. 321:
"Christians shall not Judaize and be idle on Saturday [in the original: "sabbato" shall not be idle on the Sabbath], but shall work on that day; but the Lord's day they shall especially honour, and as being Christians, shall, if possible, do no work on that day. If, however, they are found Judaizing, they shall be shut out ["anathema,"--excommunicated] from Christ."
Council of Laodicea, c. A.D. 337, Canon 29, quoted in C.J. Hefele, "A History of the Councils of the Church," Vol. 2, p. 316.