Moesia, in classical geography, was a region to the south of the Danube, corresponding pretty closely to the modern Servia and Bulgaria. The original inhabitants, probably Thracians, were subdued by a body of Celtic invaders in B.C. 277. The Roman province, formed in the reign of Augustus, was subsequently divided into two Mcesia Superior (Servia), and Moesia Inferior (Bulgaria) - probably soon after the accession of Trajan. The Goths first appeared in Moesia in 250 A.D.; the Visigothic settlement took place under Valens in 376. The irruption of the Slavonians and Bulgarians began in the 5th century and continued till the 7th century.