Amadocus was a ruler in 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...

, who inherited in conjunction with Berisades

Berisades

Berisades was a ruler in Thrace, who inherited, in conjunction with Amadocus II and Cersobleptes, the dominions of the Thracian king Cotys on the death of the latter in 358 BC...

 and Cersobleptes

Cersobleptes

Cersobleptes was son of Cotys, king of Thrace, on whose death in 358 BC he inherited the kingdom in conjunction with Berisades and Amadocus II, who were probably his brothers. He was very young at the time, and the whole management of his affairs was assumed by the Euboean adventurer, Charidemus,...

 the dominions of Cotys, on the death of the latter in 358 BC

358 BC

Year 358 BC was a year of the pre-Julian Roman calendar. At the time, it was known as the Year of the Consulship of Ambustus and Proculus...

. Amadocus was probably a son of Cotys and a brother of the other two princes, though this is not stated by Demosthenes

Demosthenes

Demosthenes was a prominent Greek statesman and orator of ancient Athens. His orations constitute a significant expression of contemporary Athenian intellectual prowess and provide an insight into the politics and culture of ancient Greece during the 4th century BC. Demosthenes learned rhetoric by...

. The area controlled by Amadocus was west of the river Hebrus.

When Cersobleptes negotiated with Philip II of Macedon

Philip II of Macedon

Philip II of Macedon "friend" + ἵππος "horse" — transliterated ; 382 – 336 BC), was a king of Macedon from 359 BC until his assassination in 336 BC. He was the father of Alexander the Great and Philip III.-Biography:...

ia for a combined attack on the Chersonese

Chersonese

Chersonese is a name that was given to several different places in ancient times. The word is Latin; it derives from the Greek term for "peninsula", chersonēsos, from chersos + nēsos ....

, Amadocus refused to allow Philip passage through his territory, in consequence of which the scheme came to nothing.

Both Amadocus and Cersobleptes appear to have been subjected by Philip early in 347 BC, not long after Cetriporis

Cetriporis

Cetriporis was a was a king of the Odrysian kingdom in western Thrace from ca. 352 BC, in succession to his father Berisades, with whom he may already have been a co-ruler. He and his father had entered into an alliance with Athens and the Illyrians against Philip II of Macedonia in 358 BC...

, the son and successor of Berisades, suffered the same fate. The two rulers, having appealed to the Macedonian ruler to arbitrate a dispute between them, were then been forced to acknowledge his suzereinty when the "judge" showed up with an army.

Amadocus seems to have had a son of the same name. His successor, however, appears to have been Teres III

Teres III

Teres III was a king of the Odrysians in Thrace in ca. 149 BC, the son of Cotys IV....

.