In antiquity Krujë was a site used for pagan rituals, while after the spread of Christianity a church dedicated to Saint Alexander was built near Mount Krujë. In the late 9th century David of Krujë is mentioned as one of the bishops, who participated in the Fourth Council of Constantinople. In the early 10th century Krujë had a Byzantine Orthodox suffragan bishop, subject to the metropolitan bishop of Durrës. The Roman Catholic bishopric of Krujë was established in 1167, when its bishop was consecrated by Pope Alexander III. In 1284 the Byzantine Empire expelled the Catholic bishop of Krujë, while after Stefan Uroš II Milutin captured the town, he also expelled the Catholic bishop Andreas Croensis in 1317.
In Illyricum Sacrum Daniele Farlati documented fourteen Catholics bishops of the town from 1286 to 1694, while Konrad Eubel documented four additional bishops. Bektashism was introduced in the region of Krujë in the early 18th century. During the Ottoman era a tekke dedicated to the Bektashi saint Sari Saltik was built near the church of Saint Alexander. In 1789–99 the Dollma tekke was built by the Dollma family near the castle. In 1807 Sheikh Mimi, sent by Ali Pasha to Krujë founded another tekke in the town. However, Sheikh Mimi was executed by Kaplan Pasha, who destroyed the tekke, which was restored by Baba Husayn of Dibër in the middle 19th century
