Alexander the Great came to power in 336 B.C. He was the son of Philip II, the King of Macedonia. After Philip II was assassinated, Alexander became King Alexander III.
In 340 B.C., while his father invaded Thrace, Alexander was left in charge of Macedonia as regent. In 338 B.C., Philip II made Alexander a commanding general of the Macedonian army. Under his military leadership, the Macedonians were successful in their invasion of Greece. In 336 B.C., Philip II was assassinated after launching an invasion of the Persian Empire. Alexander succeeded his father as King Alexander III. He completed the invasion his father had begun, gaining power over the Persian Empire.