I know he prefered sculpting to painting but what is the history behind his reluctance to paint the famous ceiling?
Hmm. He’d been called to Rome to put together Julius II’s tomb, a great big sculptural job. . . then Julius decided he wanted the chapel painted first. This is perhaps because they’d started on new St Peter’s, and he’d want the tomb there instead of the old cathedral so he put off the sculpting project for a bit. Mike believed that Julius had put the brakes on the sculpture project in order to divert money to the church building and was changing the plans for the tomb to something more modest to cut costs. This could have offended his ego and sense of artistic integrity.
So aside from being primarily a sculptor and preferring that, it may have been that he was pissed off about having the project back-burnered and underfunded. After that point, history takes over, first in Vasari (although I don’t know what he reports) and then probably in the Agony and the Ecstacy-- haven’t seen the whole thing but it’s’. . . a liberal retelling, from what I’ve heard. The Mike mythology is greatly built up, generally.