Alcek or Alzeco was allegedly a son of Kubrat and led the Altsikurs to Ravenna that later settled in the villages of Gallo Matese, Sepino, Boiano and Isernia in the Matese mountains of southern Italy.
Alzeco should not be confused with the Pannonian Bulgar leader Alciocus who joined the Wends before Alzeco was born.
After the collapse of Old Great Bulgaria, some of the Bulgars, led by Alzeco, thought to be a son of Khan Kubrat, settled in the lands of the Longobard Kingdom. Paul the Deacon places a settlement in his history of the migration of the Bulgars in the area of the Duchy of Benevento. Under the leadership of Alzeco, the Bulgars (called "Vulgars" by Paul) came to Italy in Benevento, where they settled in the Molise region.
The earlier Khagan called Alciocus who was the leader of Bulgar hordes of the Avar Khanganate, is also known. The main source for these events is the medieval chronicle of Fredegar. In 631 Samo led a rebellion against the Pannonian Avars. Alciocus fled with 9,000 Bulgars to Bavaria where he asked the Frankish king Dagobert II for a piece of land to settle in. The king at first allowed them some land, but one night he ordered his army to slaughter the Bulgars. Only 700 out of 9,000 survived the slaughter and fled for protection to Walluc king of the Wends. 
After the departure of Alciocus, Kubrat established peace between the Avars and Byzantium in 632.
Although only three of Kubrat's sons are mentioned by name it has been suggested that Kubrat gave the name Alzeco to one of his other two sons.
After Kubrat's death over 40 years later, his empire was divided by his five sons in the 670s.
Alzeco gained permission from the King of the Lombards, Grimoald, to settle in the area of Ravenna. Eventually they were sent south into the Duchy of Benevento, where Alzeco was granted the rule of their settlements with the Longobard (Italian) title of gastald.
Human graves of a steppe-nomadic character as well as horse burials datable to the second half of the eighth century attest to the presence of Pannonian peoples in the Molise and Campania. In the lifetime of Paul the Deacon, he recorded that the descendants of these "Vulgars" still spoke their original language, as well as Latin.
Less careful researchers have, in the past, claimed one identification of both historical figures. They have suggested that Alzeco might be identified with the Bulgar leader Alciocus of the Fredegar chronicle. This notion, however, must surmount a significant chronological contradiction, and it is possible that this was a title rather than a personal name.