Valentinian III was a Roman Emperor who ruled from 425 to 455 AD. He was born on July 2, 419, and became emperor at a young age after the death of his predecessor, Theodosius II. His reign was marked by political instability and the increasing power of military leaders. During his rule, the Western Roman Empire faced numerous challenges, including invasions by the Vandals and internal strife. Valentinian III struggled to maintain control and relied heavily on influential generals like Aetius. His reign ended when he was assassinated in 455, leading to further decline in the empire.