Mastino had himself cherished the project of an Italian Kingdom; but he died before approaching its accomplishment.  The degeneracy of his house began with his three sons.  The two younger killed the eldest; of the survivors the stronger slew the weaker and then died in 1374, leaving his domains to two of his bastards.  One of these, named Antonio, killed the other in 1381,[2] and afterwards fell a prey to the Visconti in 1387.  In his subjugation of Verona Gian Galeazzo contrived to make use of the Carrara family, although these princes were allied by marriage to the Scaligers, and had everything to lose by their downfall.  He next proceeded to attack Padua, and gained the co-operation of Venice.  In 1388 Francesco da Carrara had to cede his territory to Visconti’s generals, who in the same year possessed themselves for him of the Trevisan Marches.  It was then that the Venetians saw too late the error they had committed in suffering Verona and Padua to be annexed by the Visconti, when they ought to have been fortified as defenses interposed between his growing power and themselves.  Having now made himself master of the North of Italy,[3] with the exception of Mantua, Ferrara, and Bologna, Gian Galeazzo turned his attention to these cities.  Alberto d’ Este was ruling in Ferrara; Francesco da Gonzaga in Mantua.  It was the Visconti’s policy to enfeeble these two princes by causing them to appear odious in the eyes of their subjects.[4] Accordingly he roused the jealousy of the Marquis of Ferrara against his nephew Obizzo to such a pitch that Alberto beheaded him together with his mother, burned his wife, and hung a third member of his family, besides torturing to death all the supposed accomplices of the unfortunate young man.  Against the Marquis of Mantua Gian Galeazzo devised a still more diabolical plot.  By forged letters and subtly contrived incidents he caused Francesco da Gonzaga to suspect his wife of infidelity with his secretary.[5] In a fit of jealous fury Francesco ordered the execution of his wife, the mother of several of his children, together with the secretary.  Then he discovered the Visconti’s treason.  But it was too late for anything but impotent hatred.  The infernal device had been successful; the Marquis of Mantua was no less discredited than the Marquis of Ferrara by his crime.  It would seem that these men were not of the stamp and caliber to be successful villans, and that Gian Galeazzo had reckoned upon this defect in their character.  Their violence caused them to be rather loathed than feared.  The whole of Lombardy was now prostrate before the Milanese tyrant.  His next move was to set foot in Tuscany.  For this purpose Pisa had to be acquired; and here again he resorted to his devilish policy of inciting other men to crimes by which he alone would profit in the long-run.  Pisa was ruled at that time by the Gambacorta family, with an old merchant named Pietro at their head.  This man had a friend and secretary called