The way to Constantinople was clear and the Bulgarian army headed straight to the city without facing any resistance. There were still several fortresses in Thrace which remained in Byzantine hands, particularly Adrianople which was besieged by Krum's brother. On 17 July 813 Krum himself reached the walls of Constantinople and set his camp without hindrance. Within sight of the citizens of Constantinople, Krum who was also the high priest made a sacrifice to the Bulgar god Tangra, performed some pagan rituals, then the Bulgarians built trenches along the whole length of the city's walls, and then suddenly Krum offered peace.