which day of the week

[bplus]

Chat GPT says it was a Saturday on Jan. 1, 1 A.D., but only if you go by the Julian Calendar and count back. If you go back in time in a time machine, they didn't have our weekdays until 321 A.D. Before that there were other weekdays, like the 8 day Roman one, or 7 day ones by other groups (Christians, Jewish, Babylonians). But it wasn't universally made until 321 A.D. by Constantine.

Actually I was going for the very first day of AD in the year 0.

Remember you need to go a whole year, 365+ days before year 1 starts.

But sure, at that time nobody knew it was AD yet