Such was the state of affairs in April, 1320, when Castruccio Castracani with some Pisan auxiliaries suddenly occupying Cappiano, Montefalcone, and the bridges of the Gusciano, broke into the Florentine territory carrying death and devastation as far as Cerreto Guidi, Vinci, and Empoli; then, getting possession of Santa Maria a Monte by treachery, returned in triumph to Lucca. Afterwards, invading Lunigiana and Garfagnana, he dispossessed Spinetto Malespina of several places necessary for his own military operations and then marched with all his force to aid the siege of Genoa. This city still maintained a fierce and bloody struggle with its own exiles and the Lombard Ghibellines; war raged not only round the walls but throughout the whole Riviera, or coast district; it extended to Sicily and Naples and involved even more distant countries in its action, so that the siege of Troy itself, as Villani[d] asserts, was hardly equal to it for heroic deeds, marvellous exploits, and hard-fought battles by land and water, without any cessation either in summer or winter. The Florentines determined to prevent a junction that would probably have settled the fate of Genoa, therefore made a powerful diversion in the Lucchese states which compelled Castruccio to return ere he had joined the besiegers; avoiding an action they retreated to the frontier at Fucecchio while the enemy halted in front of Cappiano, both armies remaining nearly inactive until the advancing season drove them into winter quarters. To make amends for this inglorious campaign, more vigorous measures were pursued and an alliance was concluded with the marquis Spinetto Malespina, who, although a Ghibelline, had been too much injured by Castruccio on account of his friendship for Uguccione not to seize the first opportunity of revenge. Florentine troops were despatched to his aid, yet Castruccio was not apprehensive of anything in that quarter, but prepared with the help of a powerful body of Lombard Ghibellines for a more serious struggle on the side of Florence and soon marched to raise the siege of Monte Vettolini at the head of sixteen hundred men-at-arms. The Florentines, having only half that number, immediately retired and allowed him to devastate their territory with impunity for the last twenty days of June, after which he retired to chastise the Malespini in Lunigiana.