Located in Turkish Thrace on the southwestern slopes of the Strandzha mountains, the ancient city of Bizye (modern Vize) is well known not only as a place of exile during the early Byzantine period, but also as the home and cult center of St. Mary the Younger, a pious woman of Armenian origin who died there in 902 and was subsequently buried in the city’s cathedral. 
Bizye was a polis in the late antique province of Europe, but is later called for example a kastron. As a fortress, it played an important role during the 9th-century revolt Of Thomas the Slav, whose son fled there but then surrendered to the emperor. Symeon of Bulgaria captured Bizye, demolished it, and later rebuilt the city walls. In the 13th century Bizye was one of the larger asteis and the base of many military operations. The city was one of the focal points during the civil war of 1341-47, and its demos actively participated in the political struggle. Bizye was first captured by the Ottomans in 1368 but later returned to Byzantine rule (probably in 1411). It was once again captured by the Ottomans in 1453.
The Byzantine church commonly known as Hagia Sophia or Suleyman Paşa Camii is situated within the confines of the fortification walls on the southwestern slopes of the acropolis of Bizye. Both its size and commanding presence overlooking the Thracian plain seem to indicate that it was once the city’s principal place of worship, presumably Bizye’s cathedral. Unfortunately, little is known about the early history of Bizye’s Christian community and their cathedral. 
Saints Severos and Memnon are said to have suffered martyrdom in the city along with their companions, but it remains uncertain when the first Christian church was established there. Known as a place of exile already under emperor Valens, Bizye was an episcopal see since at least 431. It then became  an autocephalous archbishopric and metropolis in the 14th century. It served as the place of exile for several important ecclesiastical dissidents such as Maximus the Confessor.
The remains of ramparts still survive in the city. A.M. Mansel suggests that their upper part was constructed in the 6th century. On the other hand, D. Dirimtekin dates this section to the time of the Palaiologoi. The large Church of Hagia Sophia in Bizye combines the floor plan of a basilica with the elements of a cross-in-square church. C. Mango suggests, on the basis of a painted inscription, now lost, that the church was built in the late 8th or 9th century and housed the tomb of St. Mary the Younger in the 10th century. However, S. Eyice argues that the church dates to the 13th or 14th century, and may have replaced the earlier church where St. Mary was venerated. While there are no written documents that would help to elucidate the history of structural modifications and restorations in Ottoman times, the building seems to have served as the city’s principal mosque well into the twentieth century. 

Also see Church of Hagia Sophia in Bizye & Bizye Cave Monastery