The great characteristic of this period of oligarchical government is the activity and aggressiveness of the republic [Sidenote: Growth of Florentine dominions.] in its external relations. Before 1342 Florence had acquired the rule of considerable territories beyond the limits of its own _contado_, but most of these dominions were lost in the disturbances which accompanied the expulsion of the Duke of Athens. The great service which the oligarchy rendered to Florence was the recovery of its ascendency in northern Tuscany. Prato, Pistoia, Volterra, San Miniato, and several lesser towns were acquired between 1350 and 1368. In 1387 the important town of Arezzo was sold to the Florentines by Enguerrand de Coucy, who had held it as the lieutenant of Louis of Anjou. For some years after this the growth of Florence was checked by a desperate war against the encroachments of Gian Galeazzo Visconti, who threatened to unite Tuscany and Lombardy under his rule. It was in this war that Sir John Hawkwood commanded for Florence against the Milanese _condottiere_, Jacopo del Verme. After Hawkwood’s death in 1394, the republic was for a time in serious danger. To save their independence, the Florentines took the unusual step of appealing for German assistance, and urged the Elector Palatine, Rupert, who had been elected king of the Romans in opposition to Wenzel of Bohemia, to make war against the lord of Milan. The defeat of the German army at the battle of Brescia left Florence in greater straits than ever, when the sudden death of Gian Galeazzo in 1402 not only saved the Florentines from Milanese aggression, but enabled them to resume their policy of expansion. Within the next twenty years Pisa, Cortona, and Livorno had been added to the dominions of Florence.