In 336 BCE, Philip II’s Macedonia had risen to control the whole of the Greek world. His son and successor Alexandra the Great took an army to the Greek and Thracian city-states to secure their allegiance. Thebes resisted and Alexander destroyed the city to warn against rebellion; in Thrace, Alexander’s forces crushed an army of Illyrian and Thracian soldiers. Between 332–31 BCE, Alexander’s army occupied Egypt and defeated the Persians in the Battle of Gaugamela. He conquered Babylon, half of Persia and the remaining unconquered territories of Mesopotamia and Asia Minor. After subjugating Persia’s eastern provinces in southern and central Asia in 330, Alexander advanced to India where, after enduring altitude sickness, snowstorms and disease, his army took northeastern India in 326 BCE. Exhausted by years of campaigning, his army refused to march further east. Much of Alexander’s army was sent back overland to Persia while Alexander set sail to explore the Persian Gulf, reaching Susa in 324 BCE after an arduous march through harsh desert. He consolidated his rule in the conquered territories of Persia, but died in Babylon on 10/11 June 323 BCE.