April 18th marks the International Day of Monuments and Historic Sites.

The Keygubad Mosque is situated in the upper courtyard of the Shirvanshahs palace complex, positioned behind the Shirvanshahs palace building and facing the Seyid Yahya Bakuvi tomb. According to researcher Doctor of History Sara Ashurbeyli, Kaygubad was the grandfather of Sheikh Ibrahim. The mosque derives its name from Shirvanshah I Keygubad, who ruled from 1317 to 1343.

The mosque comprises a rectangular prayer hall and a small corridor preceding it. Four columns once stood in the center of the hall, supporting the dome. The portal was connected to the mosque's rectangular layout via a vestibule. Adjacent to the mausoleum entrance, a mihrab adorned the southern wall of the prayer hall.

Professor Shamil Fatullayev-Figarov, a doctor of architectural sciences, observes that the Keygubad mosque was constructed upon the foundations of an older structure. Unfortunately, the mosque fell victim to fire and destruction at the hands of Armenians during the events of 1918. Presently, only remnants of the foundation and a few arches remain from the Keygubad Mosque in the southern section of the Shirvanshahs Palace lower courtyard.