[13] In 513 BC, Persian forces led by Darius I crossed the Bosporus in a successful expedition against the Scythians, securing a frontier on the Danube in the process.

Megabazus marched westward into the Strymon Basin in 512 or 511 BC, subjugating a number of tribes along the way, including the Paeonions, whom he had deported to Asia.

[15] In keeping with Persian practice, Megabazus dispatched seven envoys around 510 BC to meet Amyntas, most likely at the palace in Aegae, to demand "earth and water.

The Persians began looking for the missing embassy, but Alexander covered it up by marrying his sister Gygaea to the general Bubares and paying him a large bribe.

[13] Historian Eugene Borza argued that by rejecting the murder of the Persian ambassadors, there is no longer any evidence that Macedonia was a vassal-state during Amyntas' reign.

[16] Nicholas Hammond, on the other hand, asserted that Macedonia remained a loyal subject as part of the satrapy of Skudra until the Persian defeat at Platea in 479 BC.