last king of Cappadocia (reigned 36 BC–c. AD 17), a Roman client during the late republic and the early empire.

Although granted the kingdom by Mark Antony, Archelaus retained his crown by making peace with Octavian (later the emperor Augustus) after Antony's defeat at the Battle of Actium (31 BC). In 20 BC Augustus added eastern Lycaonia and parts of Cilicia to his domain. Archelaus's marriage to King Polemo's widow, a granddaughter of Mark Antony, gave him indirect control of most of Pontus, an ancient district of northeastern Anatolia adjoining the Black Sea. On the accession of Tiberius (AD 14), whom he had earlier offended, Archelaus was summoned to Rome, accused in the Senate, and deprived of his throne. After his death in 17, Cappadocia was made a Roman province.

king of Macedonia from 413 to 399.

Although he acceded to power illegally, Archelaus was a capable and beneficent ruler. His father was King Perdiccas II (reigned c. 450–413) and his mother a slave. Archelaus seized the throne after murdering his uncle, his cousin, and his half brother, the legitimate heir. He then set about strengthening Macedonia by fortifying cities, constructing roads, and reorganizing the army. In an effort to spread the refinements of Greek civilization among his people, Archelaus invited many renowned artists, among them the tragedian Euripides, to his new capital at Pella. The king also celebrated Greek-style games at Dium, in Macedonia. During Archelaus' reign the Macedonian economy was strengthened through the development of trade and adoption of the Persian coin standard. His relations with other states were generally peaceful. In 420 he helped establish a pro-Macedonian oligarchy at Larissa in Thessaly. He was assassinated by one of his favourites while hunting.