Alexander conquered the Persian Empire, which stretched from the Mediterranean Sea to India and formed much of what was then considered the civilized world. Alexander's conquests furthered the spread of Greek ideas and customs in western Asia and Egypt. He thus made possible the rich culture of the Hellenistic Age. Alexander was born in Pella, the capital of the Macedonian kingdom. His mother taught him that his ancestor was the hero Achilles. His father taught him that the Macedonian kings were descended from the hero Hercules, who in Greek mythology was a son of the god Zeus. Alexander was tutored by the great philosopher Aristotle. He also received training in sports, physical fitness, and warfare. His schooling ended abruptly at the age of 16. As an 18-year-old, Alexander commanded the cavalry in his father's army during the battle that brought Greece under Macedonian control. His father was later murdered and Alexander, at the age of 20, became king of Macedonia. During his conquest of Asia Minor, Alexander used such weapons as battering rams, catapults, and mobile towers during his attack on the city of Tyre. Alexander's use of these huge seige machines introduced a new age of warfare. When Alexander's forces reached the upper Indus River Valley, in what is now Pakistan, Alexander wanted to continue toward the Ganges River. But his homesick troops were tired of traveling and refused to follow him any farther eastward. Alexander returned to Babylon, busying himself with the administration of his vast domain, which stretched from Greece to the Indus. About two years later, Alexander became seriously ill with a fever and died at the age of 32. No one succeeded Alexander the Great in the rule of his vast empire. His leading generals became governors of various areas and fought among themselves for control of the empire. Within a short time, Alexander's empire had split into a number of independent states.