By the death of Harun in 809, Nicephorus was left free to deal with the Bulgarian king, Krum, who was harassing his northern frontiers.
In 81 r Nicephonis invaded Bulgaria and drove Krum to ask for terms, but in a night attack he allowed himself to be surprised and was slain along with a large portion of his army.
Krum is said to have made a drinkingcup of Nicephorus's skull.
The town was taken by the Bulgarians under Krum in A.D.
Under their tsar Krum (802-815) the Bulgars invaded the districts of Adrianople and central Macedonia; under Simeon (893-927), who fixed his capital at Preslav, their empire extended from the Adriatic to the Black Sea.
He spent a part of his boyhood in captivity in Bulgaria, whither his family was carried by the Bulgarian prince Krum in 813.