All his life, Giordano Bruno had to deal with asses, the two legged as well as four legged variety. In her outstanding biography of the philosopher who was burned at the stake in 1600 for "impenitent, pertinacious, and obstinate" heresy," Ingrid Rowland writes of Bruno's preoccupation with the themes of asininity, which he explored in his writing and philosophy.
The humble donkey occupied a vital role during everyday life in the 16th century. A means of transportation as well as a beast of burden, it performed its many duties with a patience and forbearance that would have made Zeno proud. It was seen by many, including Bruno, as a symbol for a kind of blessed simplicity. At the same time, because of its stubbornness, the donkey could also represent obtuseness and ignorance. It was owing to this interesting mix of qualities that donkeys figured in the art and literature of Bruno's times.
In the best-selling adventures of the scheming picaro, the donkey more often than not was the natural companion of the low-born scoundrel, whose picaresque journeys through the various social classes of the Renaissance provided amusement and commentary on the issues of the day. The donkey was the peasant of the animal world, and was often portrayed in images of the Wheel of Fortune as a reminder that the luck of someone from even the lowest station in life could turn in an instant, while the mightiest person could fall. The lowly, patient, stubborn, hardworking donkey illustrated the truth that the only certainty in the world is change, and no one is immune from the ceaseless turnings of Fortuna's wheel. As Bruno himself wrote in his Heroic Frenzies,
* * * * * * * *
The lofty fall, the humble shall increase
By law of him who keeps the great machine
That, spinning quickly, slowly, in between,
Has power to dispense
Throughout the world immense
What's hidden and what everybody sees.
The above image taken from the Ship of Fools Tarot by Brian Williams.