After the Indus Valley Civilization stretched up to northeast Afghanistan, it was inhabited by the Iranic tribes and controlled by the Medes until about 500 BC when Darius the Great (Darius I) marched with his Persian army to make it part of the Achaemenid Empire. In 330 BC, Alexander the Great of Macedonia invaded the land after defeating Darius III of Persia in the Battle of Gaugamela. Much of Afghanistan became part of the Seleucid Empire followed by the Greco-Bactrian Kingdom. Seleucus I Nicator was defeated by Chandragupta Maurya and gave his daughter in peace treaty. The land was inhabited by various tribes and ruled by many different kingdoms for the next two millenniums. Before the arrival of Islam in the 7th century, there were a number of religions practiced in ancient Afghanistan, including Zoroastrianism, Surya worship, Paganism, Hinduism and Buddhism. The Kaffirstan region, in the Hindu Kush, was not converted until the 19th century.