The change of name of the town dates to the 10th century AD. Manuel Erotikos Komnenos, a Thracian soldier who became a prominent general and the father of the Byzantine emperor Isaac I Komnenos, was given lands around Kastamonu by Emperor Basil II and built a fortress there named "Kastra Komnenon" (Κάστρα Κομνηνών). Manuel came to the notice of Basil II because of his defence, in 978, of Nicaea against the rebel Bardas Skleros. The name "Kastra Komnenon" was shortened to "Kastamone", and later turkified to Kastamoni and Kastamonu.