Asparuh's victory led to the Bulgarian conquest of Moesia and the establishment of some sort of alliance between the Bulgars and the local Slavic groups (described as the Severi and Seven Slavic tribes). As Asparuh commenced to raid across the mountains into Byzantine Thrace in 681, Constantine IV decided to cut his losses and conclude a treaty, whereby the Byzantine Empire paid the Bulgars an annual tribute. These events are seen in retrospect as the establishment of the Bulgarian state and its recognition by the Byzantine Empire.