The idea that there was a force behind the workings of the world, known as fate or Fortuna, was very popular in the Middle Ages. Fortuna (along with Amore and Ingegno, Love and Ingenuity) is one of the three fundamental themes or motifs in the Decameron. The image of Lady Fortune, who withheld her gifts from some and granted them to others, caught the imagination of writers and storytellers, who used this image to help explain the fall of kings and the rise of common people. Boethius gave perhaps the best known treatment of the subject (The Consolation of Philosophy) in his discussion of why people undergo difficult hardships - such as his own incarceration - and who seemingly deserve better. His account of the randomness of fortune and the inexorable rise and fall of people from positions of power and privilege had great explicative power in later centuries.
The image of the Wheel of Fortune is important to the Decameron. Barolini says that "The Decameron could be pictured as a wheel - Fortune's wheel, the wheel of life - on which the brigata turns, coming back transformed to the point of departure" (Barolini, 534). And the text does indeed start at the point when society had reached its lowest point, the plague. Through ten days of storytelling, the narrators examine every facet of fortune and human ingenuity and end up spiritually and intellectually empowered, confident in their return to Florence.
Day two is especially replete with the activity of fortune and the seemingly random rise and fall of its characters. Andreuccio is the perfect example of this trend (II.5). The wheel does not treat everyone equally: Pasolini's adaptation of Andreuccio's tale shows just this type of unpredictable rise and fall.
(B. S.) Barolini, Teodolinda. "The Wheel of the Decameron," Romance Philology 36 (1983): 521-539; Cioffari, Vincenzo, "The Conception of Fortune in the Decameron." Italica 17 (1940): 135; Marcus, Millicent. An Allegory of Form: Literary Self Consciousness in the Decameron. Stanford: Anma Libri, 1979. See especially the second chapter, entitled "Spinning the Wheel of Fortune: The Tales of Andreuccio (II,5), Beritola (II,6) and Alatiel (II,7)."