These events took place in the year 1400, and two years afterward, died Giovanni Galeazzo, duke of Milan, whose death as we have said above, put an end to the war, which had then continued twelve years. At this time, the government having gained greater strength, and being without enemies external or internal, undertook the conquest of Pisa, and having gloriously completed it, the peace of the city remained undisturbed from 1400 to 1433, except that in 1412, the Alberti, having crossed the boundary they were forbidden to pass, a Balia was formed which with new provisions fortified the state and punished the offenders with heavy fines. During this period also, the Florentines made war with Ladislaus, king of Naples, who finding himself in great danger ceded to them the city of Cortona of which he was master; but soon afterward, recovering his power, he renewed the war, which became far more disastrous to the Florentines than before; and had it not, in 1414, been terminated by his death, as that of Lombardy had been by the death of the duke of Milan, he, like the duke, would have brought Florence into great danger of losing her liberty. Nor was the war with the king concluded with less good fortune than the former; for when he had taken Rome, Sienna, the whole of La Marca and Romagna, and had only Florence itself to vanquish, he died. Thus death has always been more favorable to the Florentines than any other friend, and more potent to save them than their own valor. From the time of the king's decease, peace was preserved both at home and abroad for eight years, at the end of which, with the wars of Filippo, duke of Milan, the spirit of faction again broke out, and was only appeased by the ruin of that government which continued from 1381 to 1434, had conducted with great glory so many enterprises; acquired Arezzo, Pisa, Cortona, Leghorn, and Monte Pulciano; and would have accomplished more if the citizens had lived in unity, and had not revived former factions; as in the following book will be particularly shown. BOOK IV CHAPTER I License and Slavery peculiar defects in republican governments--Application of this reflection to the state of Florence--Giovanni di Bicci di' Medici re-establishes the authority of his family--Filippo Visconti, duke of Milan, endeavors to make amicable arrangements with the Florentines--Their jealousy of him--Precautionary measures against him--War declared--The Florentines are routed by the ducal forces.