The Odrysian state was the first Thracian kingdom that acquired power in the region, by the unification of many Thracian tribes under a single ruler, King Teres probably in the 460's after the Persian defeat in Greece. Teres, who united the 40 or more Thracian tribes under one banner, was well known for his military abilities and spent much of his life on the battlefield. He died during a military campaign in 445 BC. Historians argue it was against the Triballi, a Thracian tribe occupying a large amount of land to the north of Thrace. He was succeeded by his second son, Sitalces, who seemed to have taken on his father's fighting prowess and used all the tribes to wage war with Macedon.