The naval battle of Ponza was fought in early August 1435, when the Duke of Milan dispatched the Genoese navy to relieve the besieged town of Gaeta,[13] which was currently under threat from the King of Aragon.

[12][13] At this critical moment Rene d'Anjou was currently imprisoned in the Duchy of Burgundy[15] and Alfonso of Aragon lost no time in stirring up his partisans in the Kingdom of Naples, whilst he himself sailed from Sicily with a large fleet to besiege Gaeta.

[3][16] The Duke of Milan (to whom the Republic of Genoa had lately submitted)[7] sided with the House of Anjou[16] and dispatched a Genoese fleet[13] in July under Biagio Assereto in order to relieve Gaeta.

[15] The two fleets met near the island of Ponza and after a long and gallant conflict,[15] which lasted for ten hours,[13] the Genoese were completely victorious.

[7] The Genoese were so utterly exasperated by the Duke's decision[2] that they started to rebel against him, drove out the Milanese garrison and overthrew his rule on 27 December 1435.