the printing press was in medieval period but only started gaining traction in the Renaissance period
books could be printed rather than written by hand
books were more easily created so more were made and so more people could access them
this meant that more ideas could be spread easily
the printing press also meant that the Church could no longer control what was written in books, so could no longer control medical educations
this meant that physicians and scientists were able to publish their own ideas and challenge people like Galen