Venice bit off more than it could chew and attempted to subjugate Ferrara, which was already subject to the Pope, both politically and commercially. But the Pope excommunicated Venice and issued a papal bull demanding the confiscation of their property and their enslavement wherever they were located. Obviously, the Pope did not have the army to enforce this bull, but Venice’s neighbors were thus encouraged to intervene, returning control of Ferrara to the Pope. Despite this misstep, Venice did not bow to the Pope and continued to control the mouth of the Po River. In 1313, the Pope revoked the bull.
