After the Fall of the First Bulgarian Khaganate, Bulgarian hordes spread through Europe. The luckiest of them settled the Middle Volga area, where they established the Volga Bulgaria and possibily gave origin to present-day Chuvash (though it is far from certain) and on the Lower Danube, where they established what was to become the nation of Bulgaria after assimilation to the local Slavs.
Other groups settled in Pannonia, Caucasus (where they may have originated the Balkar people) and Italy. The main group in Italy settled some areas of the Langobardian Duchy of Benevento, and they retained a considerable autonomy within it, under their own leaders. There are hints to suppose that Bulgarians kept a distinct culture and language for several generations after settling parts of Campania and Molise.
I wonder what if they manage somehow to establish their own polity in the area and keep their language? It would not be easy, but with some luck, they could leave a significant trace in the Southern Appenine. Possibly, present-day alt-Italy, or whatever in her place, has a "Bolgheria" region whose capital could be Isernia or Avellino, whose spoken language, though Romance, shows a distinct Altaic influence. What do you think?