In 811 Nikephoros invaded Bulgaria, defeated Krum twice, and sacked the Bulgarian capital Pliska; however, during Nikephoros' retreat, the imperial army was ambushed and destroyed in Varbishki mountain passes on July 26 by Krum.
Nikephoros invaded Bulgaria. This was in 811. Nikephoros defeated Krum twice. This was in 811. Nikephoros sacked the Bulgarian capital Pliska. This was in 811. The imperial army was ambushed and destroyed in Varbishki mountain passes on July 26 by Krum. This was during Nikephoros' retreat. This was however.