Visconti had caused countless victims of his tyranny to be tortured and strangled, and no wonder if there were strange things to be seen. One evening a swarm of poor people with candles in their hands appeared to a dishonest guardian of the poor at Perugia, and danced round about him; a great figure spoke in threatening tones on their behalf, it was St. Alo, the patron saint of the poorhouse. These modes of belief were so much a matter of course that the poets could make use of them as something which every reader would understand. The appearance of the slain Lodovico Pico under the walls of the besieged Mirandola is finely represented by Castiglione. It is true that poetry made the freest use of these conceptions when the poet himself had outgrown them.
Italy, too, shared the belief in demons with the other nations of the Middle Ages. Men were convinced that God sometimes allowed bad spirits of every class to exercise a destructive influence on parts of the world and of human life. The only reservation made was that the man to whom the Evil One came as tempter, could use his free will to resist. In Italy the demonic influence, especially as shown in natural events, easily assumed a character of poetical greatness. In the night before the great inundation of the Val d'Arno in 1333, a pious hermit above Vallombrosa heard a diabolical tumult in his cell, crossed himself, stepped to the door, and saw a crowd of black and terrible knights gallop by in amour. When conjured to stand, one of them said: 'We go to drown the city of Florence on account of its sins, if God will let us.' With this, the nearly contemporary vision at Venice (1340) may be compared, out of which a great master of the Venetian school, probably Giorgione, made the marvelous picture of a galley full of daemons, which speeds with the swiftness of a bird over the stormy lagoon to destroy the sinful island-city, till the three saints, who have stepped unobserved into a poor boatman's skiff, exorcised the fiends and sent them and their vessel to the bottom of the waters.