They contended with vehemence that the western frontier as it stood was hopelessly insecure, that a state must either advance or lose ground, and that aggression is often the only means of defence. But the policy of this party was really inspired less by these arguments, sound as they were in some respects, than by the instinctive greed for territory which had become the guiding motive of the great Italian states. The difference between the two parties was brought to a head in 1423 by the appearance of successive embassies [Sidenote: Appeals from Florence.] from Florence to demand aid against the duke of Milan. Filippo Maria had resumed his father’s schemes of aggression in Tuscany and the Romagna. Florence was forced into war to defend her independence, and her troops suffered one defeat after another. Nothing but the intervention of the great northern republic seemed likely to arrest the duke’s progress, and the appeals to Venice became more and more pressing. The first embassy in 1423 had been repulsed by the influence of Mocenigo, but he had died later in the year, and his place was filled by the election of his opponent, Foscari. Still, parties in Venice were too evenly balanced to admit of a decisive intervention in the war, and the Florentine envoys proceeded from prayers to threats. If Venice would give no aid, Florence would seek her own safety by joining with Milan. ‘When we refused to help Genoa, she made Visconti lord of the city; if you refuse to help us, we will make him king of Italy.’ At the critical moment the Florentine appeal was reinforced by the arrival of Carmagnola, who had incurred the jealous suspicion of Filippo Maria, and had been driven in disgrace from his service. His announcement that the duke would never be satisfied till he had driven the Venetians from Lombardy, and the prospect of utilising so distinguished a general against his former employer, turned the scale in favour of Foscari and his party. At the end of 1425 it was decided to join Florence in open war against the duke of Milan.