Venetian admiral Lorenzo Tiepolo breaks through Acre's harbor chain in 1257 and destroys several Genoese ships, conquers the disputed property, and destroys Saint Sabas' fortifications.

Despite throwing up a blockade, he is unable to expel from their quarter of the city the Genoese, who are eight hundred men strong and armed with fifty to sixty ballistae; there are also siege engines among the Venetians.

The famed Genoese crossbowmen are also fighting in Acre: the life of the Count of Jaffa is only spared by a chivalrous Genoese consul who has forbidden his crossbowman to shoot the count from his tower.

Pisa and Venice hire men to row their galleys in Acre itself during the siege: the average rate of pay of a Pisan- or Venetian-employed sailor on one of their galleys is ten Saracen besants a day and nine a night.

The blockade has lasted more than a year (perhaps twelve or fourteen months), but because the Hospitaller complex is also near the Genoese quarter, food is brought to them quite simply, even from as far away as from Philip of Montfort in Tyre.

The regent of the kingdom, John of Arsuf, who had initially tried to mediate, in August 1257 confirms a treaty with the city of Ancona, granting it commercial rights in Acre in return for aid of fifty men-at-arms for two years.

Ancona is an ally of Genoa and John seeks by his treaty to bring the feudatories—most of whom are onside—to support Genoa against Venice.

His plan ultimately backfires and John of Jaffa and John II of Beirut "manipulated the complex regency laws" in order to bring the feudatories of the Kingdom of Jerusalem into a position of support for Venice.

In this they have the support of the new bailiff, Plaisance of Cyprus, Bohemond VI of Antioch, and the Knights Templar.

At this juncture, Philip of Montfort, who has been providing food to the Genoese in Acre, is one of Genoa's only supporters.

Philip is staying about a mile away from Acre, in a place called "the new Vigny" (la Vignie Neuve) with "eighty men on horses and three hundred archer-villeins from his land".