Humayun (1508-1556; reigned 1530–40, 1555-56) was the second Mughal emperor, the son of Babur, and a weak and vacillating monarch whose reign almost saw the premature destruction of the empire. Excessively lenient towards his external and internal enemies alike, Humayun was driven out of northern India by Sher Shah by the early 1540s and was forced to seek refuge in Afghanistan and then in Persia. Sher Shah, who had founded a new dynasty in Delhi, died in 1545 and his son in 1554; the collapse of this new dynasty enabled Humayun to return to power in India supported by Persian arms. Shortly after gaining power, however, he died in a domestic accident, falling down the stone steps of a palace tower. He was succeeded by his son Akbar.