Ursus Hypatos (†737) (also Orso Ipato) was the 3rd doge of Venice, and probably the first to be chosen by the Venetians. He was killed in an internal struggle in 737.
The Chronicon Altinate contains an apocryphal account of how duke Paulicius was killed in a factional fight between people from Equilo and Heraclia.
The first doges, from the “Chronica per extensum descripta” (1340s) by Andrea Dandolo.
The Venetian state was always an ad hoc construct, and institutions came and went at the convenience of the ruling elite.