Archelaus I (Greek: Ἀρχέλαος Α΄) was king of Macedon from 413 to 399 BC, following the death of Perdiccas II. The son of Perdiccas by a slave woman, Archelaus obtained the throne by murdering his uncle, his cousin, and his half-brother, the legitimate heir, but proved a capable and beneficent ruler, known for the sweeping changes he made in state administration, the military, and commerce.
Almost immediately after he took power, Archelaus was faced with a situation which allowed him to completely reverse Macedon's relationship with Athens, which had been a major threat for the past half century. The Athenians experienced a crushing defeat at Syracuse in late 413 during which most of their ships were destroyed. This left the Athenians in desperate need of a huge amount of timber to build new ships and Archelaus in a position to set the price. Archelaus generously supplied the Athenians with the timber they needed. In recognition of this, the Athenians honored Archelaus and his children with the titles of proxenos and euergetes .
Archelaus went on to institute many internal reforms. He issued an abundance of good quality coinage. He built strongholds, cut straight roads (important for movement of the military), and improved the organization of the military, particularly the cavalry and hoplite infantry.
Archelaus was also known as a man of culture and extended cultural and artistic contacts with southern Greece. In his new palace at Pella (where he moved the capital from the old capital at Aigai), he hosted great poets, tragedians, including Agathon and Euripides, (who wrote his tragedies Archelaus and The Bacchae while in Macedon), musicians, and painters, including Zeuxis (the most celebrated painter of his time). Archelaus reorganized the Olympia, a religious festival with musical and athletic competitions honoring Olympian Zeus and the Muses at Dion, the Olympia of Macedon. The greatest athletes and artists of Greece came to Macedon to participate in this event.In addition, Archelaus competed and won in Tethrippon in both Olympic and Pythian Games.
According to Aelian, Archelaus was killed in 399 B.C. during a hunt, by one of the royal pages. By the time that he died, Archelaus had succeeded in converting Macedon into a significantly stronger power. Thucydides credited Archelaus with doing more for his kingdom than all of his predecessors together.