Theodosius I
Emperor
Sanctified Life
347 — 395
Also Known As
Patronage
"We authorize the followers of this law to assume the title of Catholic Christians."
The last Emperor to rule both the Eastern and Western halves of the Roman Empire, Theodosius turned the tide of history by establishing Nicene Christianity as the official faith of the state. Though a powerful ruler who navigated civil wars and the Gothic threat, his most enduring legacy is his submission to Church authority—famously accepting penance from St. Ambrose after the Massacre of Thessalonica, proving that even Caesars are subject to the Kingdom of God.

Historical Journey
Life Locations
Historical Depiction

Wikimedia Commons Source
Titles & Roles
Writings
Edict of Thessalonica
The decree declaring Nicene Christianity the official religion of the Roman Empire.
Read MorePrayers
Sacred invocations and spiritual gems from the heart of Theodosius I.
Your life was a pillar of the faith, O Theodosius; By your words and deeds you strengthened the Church, And brought the Empire to the worship of the Truth. O righteous Emperor, pray to Christ our God to grant us His great mercy.
Gallery

Roman empire 395
Shepherd, William R. • 1923
The administrative divisions of the Roman Empire in 395, under Theodosius I.
Sacred Symbols
orb and_cross
Christian Dominion
scroll
Edict of Thessalonica
Life Journey
Born in Hispania
Born in Coca, Spain, to a high-ranking military family.
Military Commander
Serves as a commander in Moesia, defeating the Sarmatians.
Emperor of the East
After the disastrous Battle of Adrianople, Gratian appoints him Emperor of the East to save the empire from the Goths.
Edict of Thessalonica
Issues the decree 'Cunctos populos', making Nicene Christianity the official state religion.
Council of Constantinople
Convenes the Second Ecumenical Council to confirm the Nicene Creed.
Penance of Milan
After ordering a massacre in Thessalonica, he is barred from the cathedral by St. Ambrose and accepts public penance.
Sole Emperor
Defeats the usurper Eugenius at the Battle of the Frigidus, briefly uniting the entire Roman Empire.
Death
Dies in Milan, leaving the empire to his two sons, Arcadius and Honorius, permanently splitting it.
Related Saints
Connections in the communion of saints
Constantine the Great
Theodosius made Christianity the sole religion of Rome, completing Constantine's vision.
Ambrose
Ambrose famously required Theodosius to do public penance for the Thessalonica massacre.
Justinian I
Justinian looked to Theodosius's codification of Christian law as a model for his own reforms.
Ambrose
Ambrose famously excommunicated Emperor Theodosius after the Thessalonica massacre, demanding public penance.