But the unfortunate Florentines were again duped of the reward which should have attended their alliance with the Ghibelline princes. Lucca was indeed ceded by Mastino for a money payment, but the Pisans intervened to prevent such an addition to the dominions of their rivals. In 1341 the Pisans defeated the forces of Florence, and in the next year they obtained the surrender of Lucca. This disappointment was the last of a series of disasters which weakened and discredited the government of the _popolo grasso_ in Florence (_vide_ p. 32). In their chagrin the citizens resorted to the expedient, so familiar in the mediæval history of Italy, of intrusting a temporary dictatorship to a foreigner. Their choice fell upon Walter [Sidenote: Walter de Brienne in Florence, 1343.] de Brienne, who had previously been active in Florence as a follower of Charles of Calabria. His ancestors had gained the duchy of Athens at the time when the Fourth Crusade had given to western princes the dominion of the eastern empire, and though his father had been forced to resign in 1312, Walter still called himself Duke of Athens. The temporary military and judicial authority intrusted to the duke failed to satisfy his ambition, and he set himself to establish a permanent despotism in Florence. It was not difficult for him to gain over the _grandi_ and the lower classes, who were jealous of the monopoly of power claimed by the wealthy burgesses. With their aid a parliament was convoked which insisted on voting the signory to the duke for his life. But ten months of arbitrary rule sufficed to disgust the most liberty-loving people in Italy, and the nobles and lesser guilds combined with the greater guilds to overthrow the despotism which had risen through the jealousy of classes. Walter de Brienne ordered his hired horsemen to ‘course the city,’ _i.e._ to gallop along the principal streets and disperse the insurgents. But the citizens had erected barricades to bar the progress of the cavalry, and the duke, besieged in the Palazzo Vecchio, was compelled to abdicate. His fall was followed by concessions to the _grandi_ who had taken an active part in the struggle. The Ordinances of Justice [Sidenote: Constitutional changes.] (_vide_ p. 32) were repealed, and the office of gonfalonier, whose original function was to enforce the ordinances, was abolished. The government was to be intrusted to twelve priors, three from each quarter of the city; and of these three, one was to be a noble and two burghers. Other offices were also thrown open to the nobles. But the old jealousy of the _grandi_ was too deeply seated to allow this arrangement to be permanent. A rising of the mob forced the four noble priors to quit the _palazzo_. The nobles took up arms to defend their cause, but the civil strife was fatal to the power of their whole class. The ordinances, and with them the office of gonfalonier, were revived, and the only permanent result of the