The troubles of Tuscany and Lombardy had brought the city of Lucca under the rule of Mastino della Scala, lord of Verona, who, though bound by contract to assign her to the Florentines, had refused to do so; for, being lord of Parma, he thought he should be able to retain her, and did not trouble himself about his breach of faith. Upon this the Florentines joined the Venetians, and with their assistance brought Mastino to the brink of ruin. They did not, however, derive any benefit from this beyond the slight satisfaction of having conquered him; for the Venetians, like all who enter into league with less powerful states than themselves, having acquired Trevigi and Vicenza, made peace with Mastino without the least regard for the Florentines. Shortly after this, the Visconti, lords of Milan, having taken Parma from Mastino, he found himself unable to retain Lucca, and therefore determined to sell it. The competitors for the purchase were the Florentines and the Pisans; and in the course of the treaty the Pisans, finding that the Florentines, being the richer people, were about to obtain it, had recourse to arms, and, with the assistance of the Visconti, marched against Lucca. The Florentines did not, on that account, withdraw from the purchase, but having agreed upon the terms with Mastino, paid part of the money, gave security for the remainder, and sent Naddo Rucellai, Giovanni di Bernadino de' Medici, and Rosso di Ricciardo de' Ricci, to take possession, who entered Lucca by force, and Mastino's people delivered the city to them. Nevertheless, the Pisans continued the siege, and the Florentines used their utmost endeavors to relieve her; but after a long war, loss of money, and accumulation of disgrace, they were compelled to retire, and the Pisans became lords of Lucca.