Antigonus III Doson was a king of the ancient Greek kingdom of Macedonia, ruling from 227 to 221 BCE. He came to power after the death of his predecessor, Antigonus II Gonatas, and was known for his efforts to stabilize the kingdom during a time of political turmoil. Antigonus III was a member of the Antigonid dynasty and played a significant role in the Hellenistic period. During his reign, Antigonus III successfully defended Macedonia against external threats, particularly from the Aetolian League and the Spartan king Cleomenes III. He is also remembered for his military campaigns, which helped to maintain Macedonian influence in Greece. His reign ended with his death in battle, leading to a succession crisis in the kingdom.