Alexander the Great appointed Ptolemy governor of Egypt.
The large empire Alexander the Great had conquered was too big for one successor. Instead, the empire was split among competitors called diadochi of epigoni. One general was entrusted with Macedonia; another Thrace; and a third Syria. One of Alexander's favorite generals, Ptolemy Soter, was made governor of Egypt. The esteem was mutual as can be seen in Ptolemy Soter's having Alexander's body brought for burial to Egypt, where it was permanently interred at the city Alexander had founded and named after himself -- Alexandria [see Map]. It is also possible to look at this gesture as politically motivated. The same can be said of Ptolemy Soter's marriage to the daughter of the most recent Egyptian pharaoh, Nectanebo II.
Ptolemy Soter established his capital at Alexandria, founded a museum, and started collecting books for a library which, under his successors, became the center for scientific research and the best collection of Greek and Roman papyri in the world. He also initiated what was to become one of the wonders of the ancient world, the lighthouse off the coast of Alexandria on the island of Pharos.
Ptolemy Soter's rule of Egypt lasted from 332-283 B.C. The son of Ptolemy Soter, Ptolemy II Philadelphos, co-ruled for the last two years of the reign of Ptolemy Soter and then succeeded him. Cleopatra was a descendant of the Macedonian general Ptolemy Soter.
Source: Haaren's Famous Men of Greece