He was heavily influenced by his eldest sister Pulcheria who pushed him towards orthodox Christianity. Pulcheria was the primary driving power behind the emperor and many of her views became official policy.
On the death of his father Arcadius in 408, he became Emperor. In June 421 Theodosius married the poet Aelia Eudocia. They had a daughter, Licinia Eudoxia, whose marriage with the Western Roman Emperor, Valentinian III, marked the re-unification of the two halves of the Empire, even if for a short time. Theodosius created the Constantinople University, and died in 450 as the result of a riding accident.
The Theodosian Code
In 429 Theodosius appointed a commission to collect all of the laws since the reign of Constantine, allegedly the first Christian emperor, and create a fully formalized system of law. This plan was left unfinished, but the work of a second commission that met in Constantinople, assigned to collect all of the general legislations and bring them up to date was completed, and their collection published as the Codex Theodosianus in 438. The law code of Theodosius II, summarizing edicts made since the first Christian emperor Constantine, provided a basis for the law code of Justinian in the following century. Roman intolerance of impiety with respect to ritual was now extended to crimes of conscience and of thought.
- Reign of Theodosius II (chapter of J. B. Bury's History of the Later Roman Empire)
- Theodosian Code: Sections concerning religious observances (English)
- George Long, "Codex Theodosianus"