Byzantine–Bulgarian war of 913–927
The Byzantine–Bulgarian war of 913–927 was fought between the Bulgarian Empire and the Byzantine Empire for more than a decade. Although the war was provoked by the Byzantine emperor Alexander's decision to discontinue paying an annual tribute to Bulgaria, the military and ideological initiative was held by Simeon I of Bulgaria, who demanded to be recognized as Tsar and made it clear that he aimed to conquer not only Constantinople but the rest of the Byzantine Empire, as well.
A Bulgarian delegation and Leo VI, Madrid Skylitzes
Above: a feast in Constantinople in honour of Simeon; below: a Bulgarian attack upon the Byzantines, Manasses Chronicle.
The Walls of Constantinople
The Byzantine soldiers take an oath on the eve of the battle of Achelous, Madrid Skylitzes.
The First Bulgarian Empire was a medieval state that existed in Southeastern Europe between the 7th and 11th centuries AD. It was founded in 680–681 after part of the Bulgars, led by Asparuh, moved south to the northeastern Balkans. There they secured Byzantine recognition of their right to settle south of the Danube by defeating – possibly with the help of local South Slavic tribes – the Byzantine army led by Constantine IV. During the 9th and 10th century, Bulgaria at the height of its power spread from the Danube Bend to the Black Sea and from the Dnieper River to the Adriatic Sea and became an important power in the region competing with the Byzantine Empire.
Part of the Pliska fortress
Khan Krum defeats the Byzantine Emperor Nicephorus I in the battle of the Varbitsa Pass, Manasses Chronicle
Emperor Simeon I: The Morning Star of Slavonic Literature, painting by Alfons Mucha
Samuel's Fortress in Ohrid