Genesis of the dispute On 9 July 1291, Venice and Padua signed a treaty of alliance to last for nine years. In 1299, Padua acted as surety for Venice in its peace treaty with
Genoa following the
War of Curzola. With the expiration of the treaty in 1300, tensions between the two cities immediately rose. The dispute that turned into open warfare began in 1303. It was a dispute over Padua's right to construct salt pans on the swampy peninsula of Calcinara on the
Lagoon near the frontier with
Chioggia. The Paduan
commune had acquired the land at Calcinara from Gualpertino, the abbot of
Santa Giustina and brother of the poet
Albertino Mussato. The salt works may have been started under the monks. Venice, however, claimed a monopoly on supplying salt to the surrounding area. They also sought to stop the Chioggians from working with the Paduans.
Preparations for war In an effort to prevent the dispute from turning into a war, Padua sent Giovanni Caligine on a diplomatic mission to Venice. Caligine may also have had a hand in the diplomatic revolution that ended in Padua's alliance with
Verona. Negotiations between Padua and Verona took place in March–April, with the personal intervention of
Alboino della Scala. The treaty with Verona was signed in Padua on 18 May 1304. Among the signatories were the poet
Lovato Lovati and his friend
Zambono di Andrea. As a result, Padua's traditional enemy remained neutral during the conflict with Venice. Padua called upon
Vicenza,
Bassano and
Treviso for support. Venice was supported by the
D'Este and
Da Camino and by the
patriarchate of Aquileia. ==War and treaty==