According to Adrian Room, the name Bitola is derived from the old Slavic word Obitel (monastery or abode), since the city was formerly noted for its monastery. When the meaning of the name was no longer understood, it lost its prefix "o". The name Bitola is mentioned in the Bitola inscription, related to the old city fortress built in 1015. Modern Slavic variants include the Macedonian Bitola (Битола), the Serbian Bitolj (Битољ) and Bulgarian Bitolya (Битоля). Other variants of the name have also historically been used (Butella by William of Tyre, Butili by Idrisi). The Aromanian name Bituli is also derived from the Slavic name. The Greek name of the city, Monastíri (Μοναστήρι), also means "monastery". The Turkish name Manastır (Ottoman Turkish: مناستر) is derived from the Greek name, as is the Albanian Manastiri.