More than ten thousand balls had been thrown at Montobbio; but the Fieschi, safe in their defences, laughed at the rage of the assailants and their own fire often seriously damaged the enemy. The people of the surrounding country scarcely concealed their sympathy for the besieged and furnished the castle with meat and provisions of every kind. The commissioners of the Republic complained of this and said that the inhabitants of Bargagli, Stroppa and other villages never brought even an egg to the camp of the Genoese, while they gave liberal supplies to the enemy. Spinola, despairing of success in the siege, united with the commissaries in urging the government to attempt a new negotiation.
At this time Doria learned of the death of king Francis, and this event removed all apprehension that the French would relieve Montobbio and attack the Spanish power in Italy. The recent victory of the emperor over Frederick of Saxony at Elbe stimulated Andrea to a more enthusiastic support of the imperial cause and to make a vigorous opposition to the proposals of accommodation which the senate assembled to discuss. He declaimed wrathfully against the shameful cowardice of making terms with traitors and declared that the Fieschi could hope nothing from France, because the new king Henry II. could not, if he wished it, devote any attention in the first month of his reign to the petty concerns of Montobbio and its handful of defenders. Though the majority of the senate favoured a treaty with Gerolamo, the powerful will of Doria prevailed and new troops were sent to Spinola. The prince sent to the duke of Florence for bombardiers, munitions and other military material of which there was a scarcity in the army of Genoa. The duke furnished these and a considerable force of infantry under Paolo da Castello; Ferrante Gonzaga sent two companies of four hundred arquebusiers, Filippo Doria was ordered by Andrea to make new surveys of the heights around Montobbio and to endeavour to place his artillery in better positions, and this general moved his guns to the less elevated height called Olmeto in our time and renewed the attack.
This bombardment produced no better results than the first one and the siege must have failed had not fortune opened a new and easier road to victory. A general order forbade any person not in the army to approach within two miles of the bastions under penalty of death. One day a soldier of the garrison dressed as a mountaineer was arrested in the act of examining the works of the besiegers, and on his person were found letters of Gerolamo to his brother Ottobuono. In these letters the count declared that he could not continue the defence for more than three months as his military supplies were insufficient for a longer period, and he urged Ottobuono to secure the immediate aid of France. Spinola was greatly encouraged by this discovery of the weakness of his adversary. He detained the soldier for some days and then, having seduced him by splendid promises, sent him back to Montobbio with a false letter of Ottobuono, in which the writer informed the count of the death of king Francis and declared that the only hope of the besieged was in an accommodation with the senate.
This intelligence greatly dispirited the garrison, in whom the want of supplies and the obstinate courage of the besiegers were beginning to produce apprehension. But desperation lent them new strength and they made several bold sorties which seriously damaged the enemy. To the want of supplies, a new and more dangerous evil was soon added. The mercenaries collected by Fieschi in the neighbouring feuds, being poorly fed and receiving no pay, began to murmur and finally refused to expose themselves to further peril. The count found that his own life was threatened by these rebellious soldiers, and in letters written on the 20th of March to Gian Maria Manara in Valditaro he asked ten faithful men to serve as a guard of his own person. Manara was a physician by profession and had so much influence with the Fieschi that they had left him to govern at pleasure the whole valley of the Taro. He furnished the men and obtained other reënforcements from captain Mengo da Montedoglio who commanded in Valditaro for Farnese. Gerolamo also sent a messenger to Cardinal Farnese to ask asylum in the church of that prelate in case he should be reduced to extremities. In this he was successful, and the cardinal also wrote to the Duke of Piacenza to give Gerolamo all possible aid.
During the first days of May the siege was prosecuted with increased vigour. The artillery of Filippo Doria poured a storm of shot into the castle, the walls fell down in large pieces and the outer curtains were ruined. There were many indications that the resistance could not long continue. Still, the subordinates of Gerolamo restored during the night the damage caused by the Ligurian and Florentine guns during the day and there was no sign of discouragement in the intrepid leaders. But the mercenaries continued to murmur and to refuse obedience to the commanders, complaining of their privations and demanding their wages. The count saw that it was necessary to surrender. Gerolamo Garaventa and Tommaso Assereto went to the camp of Spinola and offered to yield the place but on terms which the victors would not accept.
The Genoese general resolved to make a final assault upon the work. He sent trumpeters to proclaim that all who wished to save their lives must come within his lines; all who resisted the assault would be put to the sword. But though they had been many days in great privation, only two of the soldiers of Fieschi obeyed the summons. The assault was begun with great fury and, added to the discontent of the mercenaries, convinced Fieschi that he must surrender at once. He offered Spinola the castle on condition that the lives and goods of the defenders should be respected.
The senate met in Genoa to consider this proposition and the debate shows that the Fieschi had many sympathizers in the senate and that Andrea Doria was the real master of the Republic. After two days of discussion the senate resolved to accept the offers of Fieschi.The count, who knew how little value the pledges of the government really possessed, asked to be secured against the vengeance of Andrea Doria. The senate promised to secure the assent of Andrea to the negotiation and applied to him for the purpose. But the prince, who knew that Gerolamo was now in his power, refused his coöperation and the senate had not the courage to maintain their position.
The garrison at Montobbio were greatly distressed by this attitude of Doria. All means of obtaining provisions were cut off, and they must soon be reduced by starvation. Still, they held a bold front to the enemy and resolved to die fighting rather than surrender at discretion. But the mercenaries broke into open rebellion and the more desperate, after demanding their pay on the instant, seized a tower which had hitherto defied all the enemy’s guns and surrendered it to the soldiers of the Republic. The count and his faithful soldiers were obliged to take shelter in a wing of the fortress. The treason of the adventurers (which is spoken of not only in inedited documents but also by Adriani) took away all hope from the defenders. They resolved to imitate the garrison of Cariseto and retire by night over the rugged and almost inaccessible heights in their rear. But Vicenzo Calcagno reminded them that the count, who was corpulent of body, would not be able to make so fatiguing a march over wild mountain paths and that the troops of Doria held all the passes behind them. Assereto and some others resolved to risk the journey and set out; but after a fatiguing march over toilsome foot-paths they were surrounded and forced to surrender. The count who still hoped that the Republic would make good its promises yielded the castle to Spinola, who entered it with flying banners on the morning of the 11th of June.
Spinola, as a faithful servant of Andrea, ordered his Corsicans as soon as he had taken possession of the works to execute Calcagno, Manara and some other partisans of the count suspected of having participated in the murder of Gianettino. Domenico Doria, il Converso, also made some executions. The rest, including the mercenaries, were held as prisoners of war. But these last only were permitted to depart on parole. Count Gerolamo, Verrina and Assereto were reserved for public execution in the city and were treated with great inhumanity.