The hoax took place in Florence in about 1409... The victim was a carpenter named Manetto, known as Il Grasso, "the Fat Man." Manetto specialized in carving ebony and owned a shop in the Piazza San Giovanni, not far from Filippo [Brunelleschi]'s house. He was prosperous and good-natured, but one day had the misfortune of incurring Filippo's ire after missing a social gathering. Never one to resist retaliation, Filippo resolved to exact his revenge for this perceived slight by persuading a wide cast of characters to convince Manetto that he had metamorphosed into someone else....
As Manetto closed his shop one evening, Filippo went to his house near the cathedral, picked the lock, slipped inside, and barred the door behind him. When Manetto arrived a few minutes later, he rattled the door and then, to his alarm, heard what sounded like his own voice (in fact, Filippo doing an impersonation) ordering him to go away. This impersonation was so convincing that eh retreated in bewilderment into the Piazza San Giovanni. There he met Donatello, who inexplicably addressed him as Matteo, and shortly afterward a bailiff, who likewise hailed him as Matteo and then promptly arrested him for debt. He was taken to the Stinche prison, where his name was entered in the jail book as Matteo. Even his fellow prisoners--all of them party to Filippo's prank--addressed him by this alien name.
The carpenter spent a sleepless night, fretting over events but solacing himself with the thought that he was merely a victim of mistaken identity. This comfort evaporated the next morning when two strangers--the brothers of the real Matteo--arrived at the prison and claimed him as their kin. They paid his debt and liberated him, though not before chastising him for his supposed gambling and profligate living. More bewildered now than ever, he was escorted to Matteo's home on the other side of Florence, near Santa FelƬcita, where his protests that he was not Matteo, but Manetto, appeared to fall on deaf ears.... He was then put to sleep with a potion supplied by Filippo and carried, unconscious, back across the river to his own home. He was laid on his bed in a reversed position, with his head at the foot and his feet at the head.
Awakening many hours later, the poor carpenter was confused not merely by his position on the bed but also by the disarray of his house, for his tools had been completely rearranged. His perplexity grew with the arrival of Matteo's brothers... greeting him as Manetto and relating the curious story of how the previous evening their brother Matteo conceived the fantastic notion that he was someone else. The story was soon confirmed by Matteo himself--the real one--who arrived at Manetto's house to describe his puzzling dream of having been a carpenter. The disarray of the house was explained by the fact that in his dream Matteo noticed how his tools were out of order and in need of rearrangement.