his Odrysian background has been doubted, as the account of Polybius, the only remaining source (minus Livy, who relied on Polybius), called him an Odrysian only once, while also calling the Getic king Dromichaetes an Odrysian. It may thus be likely that Polybius used "Odrysian" as a synonym for "Thracian". Furthermore, after the war Cotys was described as being active in the hinterland of Abdera at the Aegean coast, implying that he was rather a Sapaean king, who are known to have resided in the Rhodopes. His identity must remain uncertain. It is a fact, however, that Cotys was the last king in the sources to be explicitly labelled an "Odrysian". There is also no evidence that Odrysians had any affiliations with the royal houses of the Sapaeans and Asti of the 1st century BC. By the middle of the 1st century BC, the Romans dominated coastal Thrace, while the most important Thracian tribes were the Sapaeans and the Asti. The Romans decided not to implement an administration in the Thracian interior, but instead relied on indirect influence via a large, Hellenized client kingdom resembling the Odrysian kingdom of old. Probably soon after the Battle of Actium in 31 BC, the Romans abolished the Asti dynasty and established the Sapaeans in Bizye, the capital of the former. The Sapaeans of Bizye created a large kingdom loyal to Rome and even expanded into the interior. Little is known about how the Sapaeans administrated this region, although they made Philippopolis a royal residence. In 21 AD king Rhoemetalces II took refuge in Philippopolis when he was confronted with a rebellion, among them Odrysians. While the historian Tacitus described them as powerful, their uprising failed due to their bad coordination. The Romans eventually dissolved the Sapaean kingdom in 45/6 and turned it into the province of Thracia. Kingship and the nature of Odrysian rule Although covering almost a third of the entire Balkan peninsula at its peak, the Odrysian kingdom is unlikely to have had state-like institutions before the reign of Seuthes III. In general, the Odrysian kingship was heavily influenced by the Persian court, while also bearing many similarities to the one practiced in Macedon. Unlike in the contemporary Greek city-states, the Odrysian kings needed to legitimize their rule by military prowess, religion and gifts. The royal gift exchange, a practice originally adopted from the Persian court, was especially important for legitimation.