Philip II expanded the power of Macedon before conquering the Greek city-states to the south. His son, Alexander the Great, then conquered Persia and extended his empire as far as India. Alexander helped spread Greek language and culture throughout his vast empire before his early death at age 32. The cause of his death remains unknown. After his death, his empire split into three kingdoms led by his generals. The city of Alexandria became a major center of commerce, science, and culture, helping to spread Hellenistic influence.