Theodosius II (401-450); also known as Theodosius the Younger and Theodosius the Calligrapher; was the son of Emperor Arcadius of the Eastern Roman Empire. He was proclaimed co-ruler and Augustus a year after his birth; becoming the youngest person to ever bear the title. He became emperor after his father's death in 408 CE; aged only seven.

His older sister Pulcheria briefly assumed regency as Augusta until Theodosius was old enough in 416 CE. Theodosius was a devout Christian; waging wars against the Sassanids and others who persecuted Christianity. He also had to deal with the Huns under Attila; forced to constantly pay them off to maintain peace.

Theodosius was also known for promulgating the Theodosian law code and for his founding of the University of Constantinople. Theodosius eventually died in 450 CE from a riding accident; leading to a power struggle between his sister Pulcheria and the eunuch Chrysaphius.