The name Madúēs (Μαδύης) or Mádios (Μάδιος) is the Ancient Greek form of a Scythian name reconstructed by János Harmatta as *Madvan, meaning "lucky" and "happy" and by Rüdiger Schmitt as *Madu, meaning "intoxicating drink".
In the 8th and 7th centuries BCE, a significant movement of the nomads of the Eurasian steppe brought the Scythians into Southwest Asia. According to Herodotus, this movement started when the Massagetae migrated westwards, forcing the Scythians to the west across the Araxes river (likely the Volga), from where they displaced the Cimmerians. The Cimmerians fled to the south along the coast of the Black Sea and reached Anatolia; the Scythians in turn pursued the Cimmerians, but followed the coast of the Caspian Sea and arrived in the region of present-day Azerbaijan, where they settled around what is today Mingachevir, Ganja and the Mugan plain, and turned eastern Transcaucasia into their centre of operations until the late 6th century BCE.
Madyes was the son of the previous Scythian king, Bartatua. His mother is unknown, but given that Bartatua had asked the hand of the Assyrian princess Serua-eterat in marriage, and that the close alliance between the Scythians and Assyria under Bartatua's reign suggested that this matrimonial alliance did happen, it is possible that Serua-eterat might have been the mother of Madyes. Bartatua's marriage to the Assyrian princess required that he would pledge allegiance to Assyria as a vassal, and in accordance to Assyrian law, the territories ruled by him would be his fief granted by the Assyrian king, which made the Scythian presence in Southwest Asia a nominal extension of the Neo-Assyrian Empire; and under this arrangement, the power of the Scythians in Southwest Asia heavily depended on their cooperation with Assyria, and henceforth the Scythians remained allies of the Assyrian Empire until it started unravelling after the death of Esarhaddon's son Ashurbanipal.
In 653 BCE, Madyes invaded the Medes, an Iranian people who were engaged in a war against Assyria, and the Median king Phraortes was killed in battle, either against the Assyrians or against Madyes. Madyes then imposed Scythian hegemony over Media for twenty-eight years on behalf of the Assyrians, thus starting a period which Herodotus called the "Scythian rule over Asia". Madyes soon expanded the Scythian hegemony to the states of Mannae and Urartu.
In 637 BCE, the Thracian Treres tribe who had migrated across the Thracian Bosporus and invaded Anatolia, under their king Kobos and in alliance with the Cimmerians and the Lycians, attacked the kingdom of Lydia during the seventh year of the reign of the Lydian king Ardys. They defeated the Lydians and captured the capital city of Lydia, Sardis, except for its citadel, and Ardys might have been killed in this attack. Ardys's son and successor, Sadyattes, might possibly also have been killed in another Cimmerian attack on Lydia in 635 BCE. Soon after 635 BCE, with Assyrian approval and in alliance with the Lydians, the Scythians under Madyes entered Anatolia, expelled the Treres from Asia Minor, and defeated the Cimmerians so that they no longer constituted a threat again, following which the Scythians extended their domination to Central Anatolia until they were themselves expelled by the Medes from Southwest Asia in the 590s BCE. This final defeat of the Cimmerians was carried out by the joint forces of Madyes, who Strabo credits with expelling the Cimmerians from Asia Minor, and of Gyges's great-grandson, the king Alyattes of Lydia, whom Herodotus and Polyaenus claim finally defeated the Cimmerians.
In 625 BCE, Cyaxares, the son of Phraortes and his successor to the Median kingship, overthrew the Scythian yoke over the Medes by inviting the Scythian rulers to a banquet and then murdering them all after getting them drunk; Madyes was likely killed during this massacre. According to Babylonian records, a decade later, around 615 BCE, the Scythians were operating as allies of Cyaxares and the Medes in their war against Assyria, and were finally expelled from Southwest Asia by the Medes in the 590s BCE, after which they returned to the Pontic Steppe.
*madu- “intoxicating drink” (in Madýēs)
A Scythian army, acting in conformity with Assyrian policy, entered Pontis to crush the last of the Cimmerians