The ideology of medicine remained mostly constant from the Middle Ages throughout most of the 16th century, with Galen’s four humors theory at the forefront. The biggest change from the Middle Ages to the 16th century occurred when the church began to allow the dissection of deceased human bodies. Leonardo Da Vinci had opportunity to examine and estimated thirty cadavers before the law was revoked. He created beautiful illustrations of the anatomy of the human body and captioned the drawings with what he estimated as the physiology. Andreas Vesalius was a pioneer of surgery, he used dissections to create anatomically correct books, which were reprinted and sold in many languages, though, perhaps his greatest achievement was that he encouraged
