Peace treaty between Byzantium and Bulgaria

In 681, Byzantium officially recognised the existence of the Bulgarian state—an event regarded as the beginning of Bulgarian statehood. This recognition resulted from Khan Asparuh’s victory over the Byzantine forces led by Emperor Constantine IV Pogonatos at the Battle of Ongal (680).
Following the defeat, the emperor was compelled to conclude a peace treaty under which Byzantium recognised Bulgaria as an independent state and undertook to pay it annual tribute. Bulgaria established itself permanently south of the Danube, in the lands of Moesia.