Mastino Della Scala with his army lay at Serio, a hamlet boasting a small eminence crowned with a strongly built but insignificant castle. Some ten miles farther Brescia was held by Julia Gonzaga's army. Only a few weeks had passed since Della Scala, falling first on Verona, and taking it, had marched on Milan and almost snatched it from Visconti's unsuspecting hold. But the alarm given at Valentine's wedding-feast had come in time. With almost superhuman energy, in two hours' time Visconti armed the walls and put the city in defense. To surprise a victory was impossible. Still, the Duke of Verona's army was only some fifteen miles from the walls, and day by day drew nearer. Visconti, from the height of proud security, was suddenly, by one move, placed in a position dangerous indeed. The towns and domains behind Milan, from that city to Turin, were still his, as were Pavia and Piacenza, but from Brescia to Verona, and from Modena to Lombardy, save for a few scattered towns and forts held desperately by Visconti's men, the whole was in the hands of Della Scala and his allies. Still Milan was not in a state of siege: men and supplies hurried in from Novara, Vercelli, and other towns in the Visconti's dominions, and powerful aid was coming to the Duke of Milan's assistance from the Empire. Yet in Visconti's eyes this aid, needful as it was, was dearly bought, for Charles IV., though an ignoble ruler and laughed at by his subjects, was of an honorable, open disposition, and related by marriage to the Estes, and the one condition on which he was dispatching to Visconti's service his soldiers stationed in Switzerland and on the borders, was that Isotta d'Este should be untouched. In the bitterness of his rage, Visconti wished he had already slain her; now, in truth, he dare not. It was no question now of gratifying an ambition, it was simple fear of losing his own throne, fear of being in his turn reduced to what he had reduced Della Scala, that made him respect the wishes of the Empire, and the feeling of the French who thronged his court. And the thought that he could not play the best card tyrant ever held, was rendered doubly bitter by the fact that Della Scala knew him to be helpless and Isotta safe. Scheming in his crafty soul for means to outwit Mastino, Visconti thought of Giacomo Carrara, who held Padua, Treviso, Cremona, Vicenza. He was Della Scala's ally, but a man of no upright soul. "Could I gain him," thought Visconti, in his musings, "I could stand without the Empire, without France, and use my captive as I please and not as they dictate." To the Estes and Julia Gonzaga he gave no thought; well he knew they were not likely to desert Mastino--but Carrara---- Meanwhile, he threw his whole strength against the opposing army, keeping it at bay, gaining time--and planning.