The Doge was the oldest and highest political position in the Venetian Republic. The word comes from the Latin dux, which means leader and was the title given to the governors of provinces in the Byzantine Empire, of which the Venice lagoon was a part in the 7th and 8th centuries, when documentation of the first doges is to be found. The initial seat of the duchy was Eracliana (Eraclea), then Metamauco (Malamocco) and finally, from 810 on, Rivus Altus (Rialto), the first nucleus of present-day Venice.
During the following two centuries, while the city was growing and becoming increasingly independent of Byzantium, the figure of the doge established itself as an elected position and became more and more powerful, with hereditary successions, conflicts and violent deaths. By the 11th century, Venice had become independent and put an end to any dynastic claims of the doge. It was decided he should be assisted by councillors and that his powers would be limited upon his election, when he was made to take the oath of the Promissione, a meticulously created set of rules that regulated both his public and private behaviour.