454 CE

Ardaric unites the Gepids with other Germanic tribes, and founds the Kingdom of the Gepids in the Pannonian Basin. Battle of Nedao: Allied forces of subjected peoples (Gepids, Heruli, Ostrogoths, Rugii, Sciri and Suebi), under the leadership of King Ardaric, defeat the Huns under Ellac, eldest son of Attila the Hun, in Pannonia. Ellac is killed during the battle and succeeded by his brother Dengizich. Ireland: The Diocese of Clogher is erected.

Geopolitics & Diplomacy

Ardaric unites the Gepids with other Germanic tribes, and founds the Kingdom of the Gepids in the Pannonian Basin.source

Conflict & Security

September 21 – Emperor Valentinian III stabs his commander-in-chief Flavius Aetius to death, during a meeting of the imperial council at Ravenna. He has accused Aetius of plotting against him to seize power. After his assassination, the Western Roman Empire has no effective defender against its hostile barbarian neighbors (Alans, Franks, Ostrogoths, Vandals and Visigoths).source
Battle of Nedao: Allied forces of subjected peoples (Gepids, Heruli, Ostrogoths, Rugii, Sciri and Suebi), under the leadership of King Ardaric, defeat the Huns under Ellac, eldest son of Attila the Hun, in Pannonia. Ellac is killed during the battle and succeeded by his brother Dengizich.source

Religion & Belief

Ireland: The Diocese of Clogher is erected.source

Births

Xian Wen Di, Chinese emperor of Northern Wei (d. 476)source
Theodoric the Great, king of the Ostrogoths (d. 526)source

Deaths

September 21 – Flavius Aetius, Roman general (magister militum)source
Dioscorus the Great, patriarch of Alexandriasource
Justa Grata Honoria, sister of Valentinian III (approximate date)source