Aspar was a powerful military leader in the Eastern Roman Empire. After Marcian's death, he passed over Anthemius, the son-in-law of Marcian and his chosen successor, and instead chose Leo I as emperor. Leo I was a loyal supporter of Aspar and had been a close friend of his son, Ardaburius.
The Reign of Marcian: A Quiz on the Eastern Roman Emperor of the 5th Century