The official documents are, for a long time, in Latin. Gradually, Venetan (Veneto) becomes the official everyday language. Many scholarly works are in Italian (i.e., Tuscan). In this account, names are shown mostly in Italian (with some Venetanized forms of clan/family names). Some technical terms are shown in Latin.
The polity and government style Comune Venetiarum is first documented in 1143; before that date, terms such as ducatus, regnum, provincia Venecie appear in documents.
The political identity of the Venetian state becomes embodied in the Serenissima Signoria di Venezia, an organ first mentioned in 1423, and confirmed in the Promissione ducale 12 May 1462, and conceptually consisting of the Doge together with the Consiglieri ducali - this combination becoming termed the Minor Consiglio - and the three Capi di Quaranta.
Under Humanistic influence, the polity becomes known as, and is eventually officially styled, Repubblica Veneta (or di Venezia) (Latin: res publica Veneta), and is qualified with the epithet borrowed from the Signoria as Serenissima Repubblica Veneta (or di Venezia).
The early dogi are styled dux Venetiarum, humilis dux provincie Venecie, etc. Until 900 each doge also has a style expressing his being - mostly ceremonial - holder of a title of the Eastern Roman ("Byzantine") imperial court, such as hypatos (ύπατος, consul), protospatharios, etc.
The style becomes stadardised as Doge di Venezia (Dux Venetiae or Dux Venetiarum). The following changes are subject to consdiderable variation, described in detail in Lazzarini (1903).
In 1265 in communications with the imperial court, diplomatic courtesy replaces the 1206 addition by dominus terrarum et insularum suae dominatione summmissarum.
Beginning 24 Sep 1349, negotiations with Hungary make mention of Dalmatia and Croatia inopportune and the style is routinely abbreviated to Dux Venetiae et cetera. This form becomes permanent with the Treaty of 18 Feb 1358, and remains in official use for all effects until the end of the office of doge in 1797.
From 1178, the functions of the doge are exercised, during the doge's impediment or during the vacancy of the ducal office, by the Consiglieri ducali. From 1205 one of them, usually the most senior of them, exercises these functions with the style Vice Doge. The holders of this office during ducal interregna are poorly identified in the sources.
Beginning in 796 and until 1009, a doge could appoint a companion doge (termed by historians co-doge or doge coregente (Latin co-dux)), with the right of succession. It is unclear whether such an appointment has a confirmation by the concilio generalis (arengo), i.e., the body of citizens. The practice is formally prohibited by the arengo in 1032 by what may be described as a first Constitutional statute.
Initially, Venice is under the Exarchate of Ravenna in the Eastern Roman ("Byzantine") Empire. Its detachment from the imperial sovereignty is gradual. Dogi are locally elected from 742. Some authors argue that attainment of sovereign independence of the Venetian polity is properly dated to 836 with the election of Doge Pietro Tradonico.