When Philippi was made a metropolitan see Polystylum was one of its suffragans. It figures as such in: the Notitiæ episcopatuum of Leo the Wise about 901-7 ; the Nova Tactica about 940; "Notices" 3 and 10 of Parthey, which belong to the thirteenth century. In 1212 Pope Innocent III mentions it among the suffragans of the Latin Archdiocese of Philippi.
In 1363 the Greek bishop Peter became Metropolitan of Christopolis and the see was united to the Archdiocese of Maronia. About the same time the city was restored and fortified by the Emperor Cantacuzenus. Cantacuzenus says that Polystylum was the ancient Abdera; this statement also occurs in a Byzantine list of names of cities published by Parthey. This is not absolutely correct: Polystylum is Bouloustra in the region of Salonica, situated in the interior of the country north of where the ruins of Abdera are found. This approximate identification does account for the way that the see of Abdera is placed among the titular sees, although such a residential see never existed.