The careers of Philip II and his son Alexander the Great (III) were interlocked in innumerable ways: Philip II centralized ancient Macedonia, created an army of unprecedented skill and flexibility, came to dominate the Greek peninsula, and planned the invasion of the Persian Empire with a combined Graeco-Macedonian force, but it was Alexander who actually led the invading forces, defeated the great Persian Empire, took his army to the borders of modern India, and created a monarchy and empire that, despite its fragmentation, shaped the political, cultural, and religious world of the Hellenisti