The Kingdom of the Lombards was established by Alboin following the Lombard invasion in 568–569. It existed until 774, when Charlemagne conquered it, and created a Carolingian Kingdom of Italy, which late became part of the Holy Roman Empire.
The Liber Pontificalis for Gregory II (715–731), recounts in great detail the conflicts between the Eastern Roman Empire and the Papacy, with repeated attempts at the life of the pope.
Venice started as a Byzantine duchy, ruled by a “dux”, but at some point, they started choosing their own dux — or doge. When, or even who, is not clear.
Following the Lombard invasion and conquest of Venetia, a part of the Venetian population of the mainland cities fled or left for the settlements in the nearby lagoons.
The Kingdom of the Lombards played a major role in early Venetian history, as it was the Lombard invasion of Italy in 568 which started the formation of later Venice.
The Lombard invasion of Byzantine Italy in 568 was a pivotal event in Venetian history, as it kicked off the movement towards a distinct Venetian society, culture and, ultimately, state.