By 500 BC, the Persian Empire controlled the Greek city states in Asia Minor and Macedonia. Attempts by some of the Greek city-states of Asia Minor to overthrow Persian rule failed, and Persia invaded the states of mainland Greece in 492 BC, but was forced to withdraw after a defeat at the Battle of Marathon in 490 BC. In response, the Greek city-states formed the Hellenic League in 481 BC, led by Sparta, which was the first historically recorded union of Greek states since the mythical union of the Trojan War. A second invasion by the Persians followed in 480 BC. Following decisive Greek victories in 480 and 479 BC at Salamis, Plataea, and Mycale, the Persians were forced to withdraw for a second time, marking their eventual withdrawal from all of their European territories. Led by Athens and Sparta, the Greek victories in the Greco-Persian Wars are considered a pivotal moment in world history, as the 50 years of peace that followed are known as the Golden Age of Athens, the seminal period of ancient Greek development that laid many of the foundations of Western civilization.