Caboga then determined to begin the attack on Ragusa with his insurgents. The town was at that time a first-class fortress. The Porta Ploce was defended by the Revellino, and the Porta Pile by the Forte San Lorenzo; while on Monte Sergio the Forte Imperiale had been erected the previous year. An assault on the latter having failed, the blockade was commenced. At first the operations were not very successful, for although Bona raised some of the people of the Primorije, the chiefs of the villages beyond Slano told him that they had been ordered by General Tomasić to swear fealty to Austria alone—a proof of that Power’s intentions with regard to Ragusa. Captain Hoste also refused to provide a landing party or a siege train. Lowen was next applied to, and he landed fifty men, appointing Caboga “Commander-in-Chief of the Insurgent Forces besieging Ragusa.” But the besiegers had no artillery, and at their headquarters at Gravosa there were only 300 or 400 men, while a party of the French-Ragusan National Guard, under Colonel Giorgi, had succeeded in arresting some of the nobles at Gravosa on November 25. Montrichard, who commanded the Ragusan garrison, determined on a sortie on the night of December 8. Native spies informed the besiegers of the plan, and an ambuscade was prepared to meet the attacking party as they issued from Porta Pile. But midnight, the hour fixed for the sortie, having passed, and no one appearing, the insurgents thought that the idea must have been given up, and returned to Gravosa. Then a Croatian detachment under Grgurić, and an Italian one under Paccioni, issued forth from Ragusa and attacked the insurgents’ headquarters at 2 A.M. But the advance was revealed by two deserters who fired off their rifles, and Paccioni failed to co-operate with Grgurić. The sortie was therefore repulsed, but with small losses on either side.