Anti-Nicene Fathers Thought Jesus Would Return on a Sunday

Here's the Ante-Nicene quote about a Sunday rapture...

225 AD The Didascalia

"The apostles further appointed: On the first day of the week let there be service, and the reading of the Holy Scriptures, and the oblation, because on the first day of the week our Lord rose from the place of the dead, and on the first day of the week he arose upon the world, and on the first day of the week he ascended up to heaven, AND ON THE FIRST DAY OF THE WEEK HE WILL APPEAR AT LAST WITH THE ANGELS OF HEAVEN."

The "Great Apostasy" is Judaized Christianity.

597 AD Gregory I

"It has come to my ears that certain men of perverse spirit have sown among you some things that are wrong and opposed to the holy faith, so as to forbid any work being done on the Sabbath day. What else can I call these [men] but preachers of Antichrist, who when he comes will cause the Sabbath day as well as the Lord's day to be kept free from all work. For because he [the Antichrist] pretends to die and rise again, he wishes the Lord's day to be had in reverence; AND BECAUSE HE COMPELS THE PEOPLE TO JUDAIZE THAT HE MAY BRING BACK THE OUTWARD RITE OF THE LAW, AND SUBJECT THE JEWS TO HIMSELF, he wishes the Sabbath to be observed.