Yet, in general, despite Greek colonization in such areas as Byzantium, Apollonia and other cities, the Thracians avoided urban life. The first Greek colonies in Thrace were founded in the 8th century BC. Thracian tribes remained divided and most of them fell under nominal Persian rule from the late 6th century till the first half of the 5th century, until King Teres united most of them in the Odrysian kingdom around 470 BC, probably after the Persian defeat in Greece, which later peaked under the leadership of King Sitalces (431–424 BC) and of Cotys I (383–359 BC). At the commencement of the Peloponnesian war Sitalces entered into alliance with the Athenians, and in 429 BC he invaded Macedon (then ruled by Perdiccas II) with a vast army that included 150,000 warriors from independent Thracian tribes. Cotys I on the other hand, went to war with the Athenians for the possession of the Thracian Chersonese. Thereafter the Macedonian Empire incorporated the Odrysian kingdom and Thracians became an inalienable component in the extra-continental expeditions of both Philip II and Alexander III (the Great). Ever since the Macedonian king Amyntas I surrendered his country to the Persians in about 512-511 BC, Macedonians and Persians were strangers no more. Subjugation of Macedonia was part of Persian military operations initiated by Darius the Great (521–486 BC). In 513 BC - after immense preparations - a huge Achaemenid army invaded the Balkans and tried to defeat the European Scythians roaming to the north of the Danube river. Darius' army subjugated several Thracian peoples, and virtually all other regions that touch the European part of the Black Sea, such as parts of nowadays Bulgaria, Romania, Ukraine, and Russia, before it returned to Asia Minor. Darius left in Europe one of his commanders named Megabazus whose task was to accomplish conquests in the Balkans. The Persian troops subjugated gold-rich Thrace, the coastal Greek cities, as well as defeating and conquering the powerful Paeonians. Finally, Megabazus sent envoys to Amyntas, demanding acceptation of Persian domination, which the Macedonian accepted. Following the Ionian Revolt, the Persian hold over the Balkans loosened, but was firmly restored in 492 BC through the campaigns of Mardonius.