AD 811: Byzantine–Bulgarian War: Emperor Nikephoros I organises a new campaign against the Bulgarian Empire, gathering an expeditionary force (most of the Roman army) from all parts of the empire. He is accompanied by high-ranking officials and aristocrats, including his son Stauracius and brother-in-law Michael I Rangabe (both later emperors temporarily). Krum, ruler (khan) of Bulgaria, sends envoys to sue for peace. Nikephoros refuses to accept the terms and marches through the Balkan passes towards Pliska, the Bulgarian capital.