Flavius Theodosius was born in 347. His father was a senior military officer and in 368 they traveled together to Britannia to battle together. In 374 he was promoted to position of military commander of Moesia but following the execution of his father, he retired to Cauca.
Following the death of Emperor Valens in 378, Gratian appointed Theodosius as ruler of the east and when Gratian was killed in 383 and Valentinian II who was ruler of the west passed away in 392, it was Theodosius who was left as sole emperor of the entire empire.
During the reign of Theodosius the eastern empire was relatively quiet but the west proved to be a challenge with several battles with the Goths over an extended period of time.
It was usurper Maximus who also added turmoil to the west after proclaiming himself emperor in 383. He had the control of every region except for Italy and it was in 387 when he invaded Italy that Theodosius was able to execute him.
This wasn’t the last of Theodosius’s problems however, as following the death of Valentinian Arbogast took it upon himself to elect Eugenius as ruler, the two armies battled and Eugenius was defeated.
Theodosius passed away in 395 due to unknown reasons.