Apros was an ancient Greek city in Thrace, now in modern Turkey. Its exact location seems to be Kermeyan as mentioned in tr.wikepedia Kermeyan entry, near Rodosto (modern Tekirdağ, Turkey), west of Istanbul.
In the fourth century, Apros was the principal city of the region southwest of Heraclea.
Apros was a metropolitan see of the Roman Catholic Church from the time of Emperor Manuel I Comnenus (ruled 1143 - 1180) called Theodosiopolis. Either Theodosius I or Theodosius II had attempted to rename Apros to Theodosiopolis, but only the Catholic Church seems to have adopted the name for any length of time.
After the capture of Constantinople during the Fourth Crusade the city of Apros was alternately held by Tsar Kaloyan of Bulgaria and the Crusaders. The Crusaders referred to Apros as Naples or Napoli. The Crusaders made Theodosius Branas (who Geoffroi de Villehardouin refers to as Vemas) the Lord of Apros.
In 1206, Tsar Kaloyan destroyed Apros, but it was later rebuilt and continued to be ruled by Branas. In July 1305, in the Battle of Apros, the Catalan Company annihilated the Byzantine imperial army under Michael IX Palaiologos.