In the third century AD, it was threatened by Gothic raids. The Roman army that was based in Asia minor was spread thin, and the navy had moved west from the Northern city of Sinope, therefore the provincials were left exposed. These Goths came from the trans-danubian region on the black sea. When the city was under threat, the people used dedicatory statues to build their wall quicker, indicating their rush to protect themselves against the invaders. (see Mitchell - crisis and continuity (1993) page 236)
Byzantine emperorManuel I Comnenus fortified Dorylaeum in 1175, but according to some authorities the Turks recaptured it in 1176 after the Battle of Myriokephalon. However, the contemporary Byzantine historian Niketas Choniates relates that Manuel did not destroy the fortifications of Dorylaeum, as he had agreed to do as part of the treaty he negotiated with the Seljuk Turkish sultan Kilij Arslan II immediately after Myriokephalon. The sultan's response to this development was not a direct attack on Dorylaeum but the dispatch of a large army to ravage the rich Meander valley to the south.
Dorylaeum was described by the Muslim author al-Harawi (died 1215) as a place of medicinal hot springs on the frontier at the end of Christian territory.
Seven bishops are known from the fourth to the ninth century, the most famous being Eusebius. The see is mentioned as late as the twelfth century among the suffragans of Synnada, but must have been suppressed soon after.
Gherardo Sante Menegazzi, O.F.M. Cap. (1938.07.01 - 1938.10.20), as emeritus Bishop of Comacchio (Italy) (1920.12.16 - 1938.07.01), later Titular Archbishop of Pompeiopolis in Paphlagonia (1938.10.20 - death 1945.01.21)
Joseph Wilhelmus Maria Baeten (1945.11.30 - 1951.02.18) as Coadjutor Bishop of Breda (Netherlands) (1945.11.30 - 1951.02.18), succeeded as Bishop of Breda (1951.02.18 - 1961.09.08), emeritus as Titular Archbishop of Stauropolis (1961.09.08 - 1964.08.26)