Theodosius I (; 11 January 347 – 17 January 395), also known as
Theodosius the Great, was
Roman Emperor from AD 379 to AD 395. Theodosius was the last emperor to rule over both the
eastern and the
western halves of the
Roman Empire. On accepting his elevation, he campaigned against
Goths and other barbarians who had invaded the Empire; he failed to kill, expel, or entirely subjugate them, and after the
Gothic War they established a homeland south of the
Danube, in
Illyricum, within the empire's borders. He fought two destructive civil wars, in which he defeated the usurpers
Magnus Maximus and
Eugenius at great cost to the power of the Empire.