But continuing on with significant mathematical contributions from ancient Greece, we have Euclid. We don't know all of the exact details of his birth and his death. But he is the father of modern geometry. And as you can see in this map here, he didn't live in what we call Greece proper today. He lived in Alexandria, a city established by Alexander the Great. And this is during the Hellenistic period, where all of the territory that had, or most of the territory that had been conquered by Alexander the Great, was still ruled by his successors. Egypt was ruled by Ptolemy, establishing the Ptolemaic dynasty in the time of Euclid.