The Church of the Pantobasilissa (Turkish Kemerli Kilise) is a Late Byzantine church from Trigleia in the region of Bithynia. The importance of the Pantobasilissa (which translates from the Greek as “All-Blessed, the Virgin Mary”) derives from its structural and decorative characteristics.
During the thirteenth century, when the Crusaders occupied Constantinople, the region of Bithynia - situated in what is, today, northwest Turkey - was the center of Byzantine government. But, by the early fourteenth century, it had fallen to the Ottoman Turks. Over the course of the next several decades, Bithynia witnessed a fascinating range of architectural activity. Byzantine social and religious institutions lingered, however, leaving a legacy that was observable especially in the region’s architecture. Today, while very few examples of Late Byzantine buildings survive in Bithynia, the Pantobasilissa is an important building for the period.
Though the Ottomans ruled the region - in towns on the southern coast of the Sea of Marmara, Trigleia among them, the population remained largely Christian and the influence of the Byzantine legacy remained salient. The dates of the construction of the Pantobasilissa tell this story of cultural convergence. Constructed after 1336 in Trigleia, the church is almost contemporaneous with the Orhan Mosque (built around 1339) in Bursa, one of the earliest Ottoman commissions in the region. 
The church measures about 11 by 8.5 meters. The dedication and the fresco program, which depicts scenes from the life of the Virgin Mary, indicate that the church was dedicated to the mother of Christ. In the northern crossing, facing east above a Corinthian capital, is a representation of Joachim’s offerings being rejected, an early scene from the life of the Virgin Mary. In the depiction, Joachim moves forward, carrying a lamb in his veiled hands. Anna, the mother of the Virgin Mary, who appears to be helping to carry the lamb, moves back toward her husband. On the south wall of the southwest bay, a larger-than-life-size figure of the Archangel Michael complements the Marian cycle. Michael is dressed in an imperial costume, holding a staff in his right hand and a globe in his left. In the lunette above him is an eight-pointed star that apparently included more details within its lines; whatever those details were can no longer be detected. Eight-pointed stars appeared as the representation of heavenly light in the frescoes of fourteenth-century churches in Serbia and Greece and post-Byzantine decorative church programs in Cyprus. The symbol likely had a similar resonance here.