Afterward Venice underwent many political changes, among which one of the most interesting to students of history is that of the institution of the dogeship, as hereafter related.  This step was taken for more than one reason of internal organization and policy, and it was also made urgent by the encroachments of the Lombards, which had become a menace to Venetian territory and commerce.

The republic (Venetian) on her part contemplated with inquietude the rise of one monarchy after another on the skirts of the Lagoon, for the Venetians not unnaturally feared that as soon as these fresh usurpers had established themselves, they might form the design of adding the islands of the Adriatic to their dominion, and of acquiring possession of the commercial advantages which belonged to the situation held by the settlers.  For the Lombards, though not ranking among maritime communities, were not absolutely strangers to the laws of navigation, or to the use of ships, which might place them in a position to reduce to their control a small, feeble, and thinly peopled area, separated from their own territories only by a narrow and terraqueous strait.  Moreover, the predatory visits of Leupus, duke of Friuli, whose followers traversed the canals at low tide on horseback, and despoiled the churches of Heraclia, Equilo, and Grado, soon afforded sufficient proof that the equestrian skill of the strangers was capable of supplying to some extent any deficiency in nautical knowledge.

Venice at present formed a federative state, united by the memory of a common origin and the sense of a common interest; the arrengo, which met at Heraclia, the parent capital, at irregular intervals to deliberate on matters of public concern, was too numerous and too schismatical to exercise immediate control over the nation; and each island was consequently governed, after the abolition of the primeval consulate, in the name of the people, by a gastaldo or tribune, whose power, nominally limited, was virtually absolute.  This administration had lasted nearly two centuries and a half, during which period the republic passed through a cruel ordeal of anarchy, oppression, and bloodshed.  The tribunes conspired against each other; the people rebelled against the tribunes.  Family rose against family, clan against clan.  Sanguinary affrays were of constant occurrence on the thinly peopled lidi, and amid the pine-woods, with which much of the surface was covered; and it is related that in one instance at least the bodies of the dead were left to be devoured by beasts and birds of prey, which then haunted the more thickly afforested parts.

Jealousy and intolerance of the pretensions of Heraclia to a paramount voice in the policy of the community may be securely assigned as the principal and permanent source of friction and disagreement; but the predominance of that township seems to have resisted every effort of the others to supplant its central authority and wide sphere of influence; and during centuries it preserved its power, through its ostensible choice as the residence of the most capable and influential citizens.