Indian subcontinent to the list of Persian-controlled provinces. Expansion to the west began about 516 BC when Darius moved against the Greek colonies along the coast of Asia Minor. Xerxes (486-465 BC), son and successor of Darius I, was determined to continue the Persian conquest of the west and is best known for his massive invasion of Greece from across the Hellespont in 480 BC, a campaign marked by the battles of Thermopylae, Salamis and Plataea. Although successful in the pacification of Egypt and suppression of a Babylon revolt, his defeat by the allied Greek city-states spelled the beginning of the decline of the Persian Empire. Soured by these reversals, Xerxes retired to his palaces at Susa and Persepolis. In his last years, he squandered the once-enormous treasury he had gathered through trade and taxation by launching vast construction programs, most never finished. The death of Xerxes was the final turning point in Persian influence. Occasional flashes of vigor and ability by some of Xerxes' successors were too infrequent to prevent eventual collapse. The final act was played out during the reign Darius II (423-404 BC), who rose to the throne through palace intrigue. Darius was able to put down yet another rebellion in Egypt in 337-336 BC, but the beginning of the end came soon afterward with his defeat at the Battle of Granicus (334 BC) by Alexander the Great. Persepolis fell to the young Macedonian conqueror in April 330 BC, and Darius, the last Achaemenid, was murdered in the summer of the same year while fleeing the Greek forces. In the struggle for power after Alexander's death, Seleucus I brought under his control the Persian provinces of Alexander's empire. But this unity was short-lived, as the Indian holdings successfully revolted and the Seleucid kingdom broke into the competing nations of Parthia and Bactria. The last vestiges of Persian culture disappeared with the advent of Islam and the Arab conquest (640-829 AD) of Iran.