I don’t know a lot about it, but I do know that a lot of nonsense is said about cadaver dissection and the Catholic Church.
Look. Here’s
Mondino di Luzzi. He’s the father of modern anatomy study. Lived hundreds of years before da Vinci.
He taught at the University of Bologna, which like all universities was primarily designed to get clerics taught theology and canon lawyers taught canon law. Medicine was an early and important field of study there, however, and it was probably the best place in Europe to learn to be a physician. Most European medical texts came from Bologna, and their ideas on maintaining “wellness” were very influential for daily life.
It was true that cadaver dissection was tightly controlled by law, because both Church and state had a lot of interest in people not playing around with corpses. The procedure was handled the same way as surgery demonstrations – the teacher (or his ostensor, or demonstrator) did the dissection, the teacher lectured about what they were seeing, and the students observed. But medical students did learn from actual bodies, even though medical schools had to ask permission to do this from the relevant temporal and/or Church authorities. (Because they were Church-run schools.) It sounds weird to us, because our medical schools have to apply for accreditation to professional bodies, and then apply for permission to dissect to government bodies.
(All medieval and ancient medical students were allowed and encouraged to dissect animals, however. Galen advocated it.)
Both pagan law (in practically every culture) and Christian law was against dissection for both avoiding abusing a corpse and for more specific reasons. There were a lot of necromancy attempts back then. (Still are, in countries like Nigeria.) There were a lot of known magic spells, potions, and alchemy recipes that called for bits of dead people. And people don’t take it well if parts-removal happens to their relatives, who should be safe underground.
So it was very important to distinguish legitimate study from creepy guys trying to create necromantic servants.