Although Macedonia enjoyed a large degree of autonomy and was never made a satrapy (i.e. province) of the Achaemenid Empire, it was expected to provide troops for the Achaemenid army. AlexanderI provided Macedonian military support to Xerxes I () during the Second Persian invasion of Greece in 480–479 BC, and Macedonian soldiers fought on the side of the Persians at the 479BC Battle of Platea. Following the Greek victory at Salamis in 480BC, AlexanderI was employed as an Achaemenid diplomat to propose a peace treaty and alliance with Athens, an offer that was rejected. Soon afterwards, the Achaemenid forces were forced to withdraw from mainland Europe, marking the end of Persian control over Macedonia.