During the 7th century BCE, the Cimmerians, a nomadic people from the Pontic steppe who had invaded the Levant, attacked Lydia several times but had been repelled by Ardys's father, Gyges. In 644 BCE, the Cimmerians invaded Lydia for the third time, led by their king Lygdamis. The Lydians were defeated, Sardis was sacked, and Gyges was killed, following which Ardys succeeded his father.
On assuming kingship, Ardys resumed the diplomatic activity with Assyria which Gyges had ended. Ardys attacked the Ionian Greek city of Miletus and succeeded in capturing the city of Priene. Most of his reign was taken up with the wars against the Cimmerians, who occupied part of Sardis in one invasion.
In 637 BCE, that is in Ardys's seventh regnal year, the Thracian Treri 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 Lydia. They defeated the Lydians again and for a second time sacked the Lydian capital of Sardis, except for its citadel. It is probable that Ardys was killed during this Cimmerian attack, and Ardys's son and successor Sadyattes might have also been killed during another Cimmerian attack in 653 BCE.
Soon after 637 BCE, with Assyrian approval and in alliance with the Lydians, the Scythians under their king 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 expelled by the Medes from Western Asia in the 590s BCE.
- Spalinger, Anthony J. (1978). "The Date of the Death of Gyges and Its Historical Implications". Journal of the American Oriental Society. 98 (4): 400–409. doi:10.2307/599752. Retrieved 25 October 2021.
- Dale, Alexander (2015). "WALWET and KUKALIM: Lydian coin legends, dynastic succession, and the chronology of Mermnad kings". Kadmos. 54: 151–166. doi:10.1515/kadmos-2015-0008. Retrieved 10 November 2021.
- 'Miletos, the ornament of Ionia: history of the city to 400 BCE' by Vanessa B. Gorman (University of Michigan Press) 2001
- Kristensen, Anne Katrine Gade (1988). Who were the Cimmerians, and where did they come from?: Sargon II, and the Cimmerians, and Rusa I. Copenhagen Denmark: The Royal Danish Academy of Science and Letters.
- Diakonoff 1985, p. 94-55.
- Grousset, René (1970). The Empire of the Steppes. Rutgers University Press. pp. 9. ISBN 0-8135-1304-9.
A Scythian army, acting in conformity with Assyrian policy, entered Pontis to crush the last of the Cimmerians
- Diakonoff 1985, p. 126.
- Phillips, E. D. (1972). "The Scythian Domination in Western Asia: Its Record in History, Scripture and Archaeology". World Archaeology. 4 (2): 129–138. Retrieved 5 November 2021.
- Bury, J. B.; Meiggs, Russell (1975) [first published 1900]. A History of Greece (Fourth ed.). London: MacMillan Press. ISBN 0-333-15492-4.
- Diakonoff, I. M. (1985). "Media". In Gershevitch, Ilya (ed.). The Cambridge History of Iran. 2. Cambridge: Cambridge University Press. p. 36-148. ISBN 978-0-521-20091-2.
- Herodotus (1975) [first published 1954]. Burn, A. R.; de Sélincourt, Aubrey (eds.). The Histories. London: Penguin Books. ISBN 0-14-051260-8.