 The main migration was headed by Altsek, a Bulgar leader who initially joined the Avar Khaganate before switching allegiance to the Germanic Lombards.Altsek and his people arrived in the Exarchate of Ravenna, where Grimoald I of Benevento invited them to populate the Duchy of Benevento.According to the "Gesta Dagoberti I regis Francorum", Altsek's Bulgars settled in what are today the communes of Isernia, Bojano and Sepino.