These city-states were independent of each other, and usually fought wars. However, there are times when city states (such as arch enemies Sparta and Athens) work together, and it is usually forcefully brought to them through outside invasions, such as, for example: Persia, where the invasion from the east brought the two city-states (& others) to fight off the outside influence. Generally after the invasion ended they went back to fighting each other.
It was "Andreas Vesalius" who was the sixteenth-century physician who published the first accurate and detailed picture of human anatomy, since he was one of the most advanced and knowledgable surgeons of his time.
