Seuthes II was a king of the Odrysian kingdom

Odrysian kingdom

The Odrysian kingdom was a union of Thracian tribes that endured between the 5th and 3rd centuries BC. It consisted largely of present-day Bulgaria, spreading to parts of Northern Dobruja, parts of Northern Greece and modern-day European Turkey...

 of Thrace

Thrace

Thrace is a historical and geographic area in southeast Europe. As a geographical concept, Thrace designates a region bounded by the Balkan Mountains on the north, Rhodope Mountains and the Aegean Sea on the south, and by the Black Sea and the Sea of Marmara on the east...

 from about 405 to 391 BC. His rule was contemporary with that of Amadocus I, who at the beginning of his own reign made him ruler of the kingdom's Aegean

Aegean Sea

The Aegean Sea[p] is an elongated embayment of the Mediterranean Sea located between the southern Balkan and Anatolian peninsulas, i.e., between the mainlands of Greece and Turkey. In the north, it is connected to the Marmara Sea and Black Sea by the Dardanelles and Bosporus...

 shore territory. Later Seuthes apparently revolted; Aristotle

Aristotle

Aristotle was a Greek philosopher and polymath, a student of Plato and teacher of Alexander the Great. His writings cover many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, linguistics, politics, government, ethics, biology, and zoology...

 mentions a King Amadocus who was attacked by his general Seuthes, probably in reference to these individuals. Seuthes proclaimed himself king at the end of the 5th century. According to Xenophon

Xenophon

Xenophon , son of Gryllus, of the deme Erchia of Athens, also known as Xenophon of Athens, was a Greek historian, soldier, mercenary, philosopher and a contemporary and admirer of Socrates...

, who was in the country in the winter of 400-399 BC, Seuthes and Amadocus were then powerful rival rulers who faced off frequently. They were ultimately reconciled with each other and made allies of Athens

Athens

Athens , is the capital and largest city of Greece. Athens dominates the Attica region and is one of the world's oldest cities, as its recorded history spans around 3,400 years. Classical Athens was a powerful city-state...

 by the Athenian general Thrasybulus

Thrasybulus

Thrasybulus was an Athenian general and democratic leader. In 411 BC, in the wake of an oligarchic coup at Athens, the pro-democracy sailors at Samos elected him as a general, making him a primary leader of the successful democratic resistance to that coup...

 in 390 BC.