Teres I (Greek: Τήρης, Ancient Greek: [tɛ́ːrɛːs]; reigned 460–445 BC) was the first king of the Odrysian kingdom of Thrace. Thrace had nominally been part of the Persian empire since 516 BC during the rule of Darius the Great, and was re-subjugated by Mardonius in 492 BC.
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.
- The Thracians 700 BC-AD 46 (Men-at-Arms) by Christopher Webber and Angus McBride, 2001, ISBN 1-84176-329-2, page 5
- The Oxford Classical Dictionary by Simon Hornblower and Antony Spawforth,ISBN 0-19-860641-9,"page 1515,"The Thracians were subdued by the Persians by 516"
- Readings in Greek History: Sources and Interpretations by D. Brendan Nagle and Stanley M. Burstein,ISBN 0-19-517825-4,2006,page 230: "... , however, one of the Thracian tribes, the Odrysians, succeeded in unifying the Thracians and creating a powerful state ..."
- The Oxford Classical Dictionary by Simon Hornblower and Antony Spawforth,ISBN 0-19-860641-9,page 1515,"Shortly afterwards the first King of the Odrysae, Teres attempted to carve an empire out of the territory occupied by the Thracian tribes (Thuc.2.29 and his sovereignty extended as far as the Euxine and the Hellespont)"
- Xenophon (8 September 2005). The Expedition of Cyrus. ISBN 9780191605048. Retrieved 24 December 2014.