Historical references to the town are mostly connected to the local episcopal see. Thus the town first appears in the Second Council of Nicea in 787, where Bishop Sisinnius took part as a suffragan of the Metropolis of Adrianople. In summer 813, during his invasion of Thrace, the Bulgarian ruler Krum captured the town, and partially destroyed it. A boundary marker from the 8th/10th centuries with the inscription "kastr[on] Gariala[s]" is displayed in the museum at Pliska.