Pulcheria - Augusta of Imperium Romanum from 415 AD to 453 AD
Aelia Pulcheria was Regent of the eastern Roman Empire during the minority of her brother Theodosius II, and empress by marriage to Marcian. She was the oldest surviving child of Arcadius and Aelia Eudoxia.

In 415, the fifteen-year old Pulcheria took over the reins of government as the guardian of her younger brother Theodosius II and was also proclaimed "Augusta" (Empress).

Pulcheria had significant political power during her brother's reign, and when he died in 450, Pulcheria provided a successor by marrying Marcian, while simultaneously not violating her vow of virginity. She died three years later, in July 453.
Pulcheria
Empress Pulcheria of the Roman Empire (East)