Alexander I (Greek: Ἀλέξανδρος ὁ Μακεδών) was the ruler of the ancient Greek Kingdom of Macedon from c. 498 BC until his death in 454 BC. He was succeeded by his eldest son, Alcetas II.
Alexander was the son of Amyntas I and Queen Eurydice (Greek: Εὐρυδίκη). He had a sister named Gygaea (Greek: Γυγαίη).
He gave his sister for marriage to the Persian general Bubares, in the late 6th century BC who was in Macedon at the time, in order to stop him from searching for Persian soldiers who had been killed by Alexander's men following his commands.
Alexander I came to the throne during the era of the kingdom's vassalage at the hand of Achaemenid Persia, dating back to the time of his father, Amyntas I, although Macedon retained a broad scope of autonomy. In 492 BC it was made to a fully subordinate part of the Persian Kingdom by Mardonius' campaign. At that time, Alexander was on the nominal Macedonian throne. Alexander further acted as a representative of the Persian governor Mardonius during peace negotiations after the Persian defeat at the Battle of Salamis in 480 BC. In later events, Herodotus several times mentions Alexander as a man who is on Xerxes' side and follows the assigned tasks.
From the time of Mardonius' conquest of Macedon, Alexander I is referred to as hyparchos by Herodotus, meaning subordinate governor. Despite his cooperation with Persia, Alexander I frequently gave supplies and advice to the rest of the Greek city states, and warned them of Mardonius' plans before the Battle of Plataea in 479 BC. For example, Alexander I warned the Greeks in Tempe to leave before the arrival of Xerxes' troops, as well as notified them of an alternate route into Thessaly through upper Macedonia. After their defeat in Plataea, the Persian army under the command of Artabazus tried to retreat all the way back to Asia Minor. Most of the 43,000 survivors were attacked and killed by the forces of Alexander at the estuary of the Strymon river. Alexander eventually regained Macedonian independence after the end of the Persian Wars.
Alexander claimed descent from Argive Greeks and Heracles, although Macedon was considered a "barbaric" state by some in Athens, whose territories were threatened by its expansion. After a court of Elean hellanodikai determined his claim to be true, he was permitted to participate in the Olympic Games possibly in 504 BC, an honour reserved only for Greeks. He modelled his court after Athens and was a patron of the poets Pindar and Bacchylides, both of whom dedicated poems to Alexander. The earliest reference to an Athenian proxenos, who lived during the time of the Persian wars (c. 490 BC), is that of Alexander I. Alexander I was given the title "Philhellene" (Greek: "φιλέλλην", fond of the Greeks, lover of the Greeks), a title used for Greek patriots.