Dissection
Human dissections were carried out by the Greek physicians Herophilus of Chalcedon and Erasistratus of Chios in the early part of the third century BC. During this period, the first exploration into full human anatomy was performed rather than a base knowledge gained from 'problem-solution' delving. While there was a deep taboo in Greek culture concerning human dissection, there was at the time a strong push by the Ptolemaic government to build Alexandria into a hub of scientific study. For a time, Roman law forbade dissection and autopsy of the human body, so physicians had to use other cadavers. Galen, for example, dissected the Barbary macaque and other primates, assuming their anatomy was basically the same as that of humans.
Anatomical Theatre of Padua
It is worth noting that in Padua already existed a well established practice of dissection since the end of the thirteenth century. In fact, a traditional legend hands down the story of avaricious man's heart found in a basket by St. Anthony; the heart is described in a scientific way, and that shows how the direct observation of the corpses was already considered essential.