t he lacked the keen decision and broad views of Gian
Galeazzo. He vacillated in policy and kept planning plots which seemed
to have no object but his own disadvantage. Excess of caution made him
surround the captains of his troops with spies, and check them at the
moment when he feared they might become too powerful. This want of
confidence neutralized the advantage which he might have gained by his
choice of fitting instruments. Thus his selection of Francesco Sforza
for his general against the Venetians in 1431 was a wise one. But he
could not attach the great soldier of fortune to himself. Sforza took
the pay of Florence against his old patron, and in 1441 forced him to a
ruinous peace; one of the conditions of which was the marriage of the
Duke of Milan's only daughter, Bianca, to the son of the peasant of
Cotignola. Bianca was illegitimate, and Filippo Maria had no male heir.
The great family of the Visconti had dwindled away. Consequently, after
the duke's death in 1447, Sforza found his way open to the Duchy of
Milan, which he first secured by force and then claimed in right of his
wife. An adverse claim was set up by the House of Orleans, Louis of
Orleans having married Valentina, the legitimate daughter of Gian
Galeazzo.[2] But both of these claims were invalid, since the
investiture granted by Wenceslaus to the first duke excluded females. So
Milan was once again thrown open to the competition of usurpers.

[1] The most complete account of Filippo Maria Visconti written by a
contemporary is that of Piero Candido Decembrio (Muratori, vol.
xx.). The student must, however, read between the lines of this
biography, for Decembrio, at the request of Leonello d' Este,
suppressed the darker colors of the portrait of his master. See the
correspondence in Rosmini's Life of Guarino da Verona.

[2] This claim of the House of Orleans to Milan was one source of
French interference in Italian affairs. Judged by Italian custom,
Sforza's claim through Bianca was as good as that of the Orleans
princes through Valentina, since bastardy was no real bar in the
peninsula. It is said that Filippo Maria bequeathed his duchy to the
Crown of Naples, by a will destroyed after his death. Could this
bequest have taken effect, it might have united Italy beneath one
sovereign. But the probabilities are that the jealousies of
Florence, Venice, and Rome against Naples would have bee