Krum arrived at the city on 17 July 813, and performed a pagan sacrificial ritual involving animals and people in order to impress and force the defenders to surrender.

But it was a failure and when Krum saw that the walls were impregnable, he decided to propose peace to the new Byzantine emperor Leo V the Armenian.

Furious, Krum ravaged the environs of Constantinople on the way home, then took Adrianople and deported its inhabitants (including the parents of the future Basil I) across the Danube.

The sack of Thrace enriched Krum and his aristocracy, and allowed the use of those architectural elements looted from the cities in the rebuilding of his capital Pliska.

Krum spent the winter preparing a major attack on Constantinople, where a rumor reported the creation of multiple artillery pieces carried on five thousand wagons.