Vize in the province of Kırklareli is the centre of what was a flourishing district in the time of Justinian. (41.576271, 27.767357) It was already a busy place in Roman times with the foundations of the fortress on the top of the hill dating from about 75BC. There is a nice Roman theatre nearby. There is one large Byzantine church, preserved over the years by conversion into a mosque.
[1]Küçük Aya Sofya / Gazi Süleyman Paşa Camii
One ecclesiastical building that was not suited to mosque conversion was the tetraconch, now mostly covered by structures associated with the Sarapdar Hasan Bey Camii.
[2]Tetraconchos of Vize
The area around Vize is dotted with cave buildings, natural shelters inhabited by humans for thousands of years and, in Byzantine times at least, shaed into churches and monasteries. Just north of Vize is Asmakayalar Monastery.
[3]Asmakayalar Monastery
[4]