The Moon is made of green cheese

"The Moon is made of green cheese" is a statement referring to a fanciful belief that the Moon is composed of cheese. In its original formulation as a proverb and metaphor for credulity with roots in fable, this refers to the perception of a simpleton who sees a reflection of the Moon in water and mistakes it for a round cheese wheel. It is widespread as a folkloric motif among many of the world's cultures, and the notion has also found its way into children's folklore and modern popular culture.

The phrase "green cheese" in this proverb simply refers to a young cheese (sometimes "cream cheese" is used), though modern people may interpret the color reference literally.

There was never an actual historical popular belief that the Moon is made of green cheese (cf., the myth of the Flat Earth). It was typically used as an example of extreme credulity, a meaning that was clear and commonly understood as early as 1638.

There exists a family of stories in comparative mythology in diverse countries that concern a simpleton who sees a reflection of the Moon and mistakes it for a round cheese:

... the Servian tale where the fox leads the wolf to believe the moon reflection in the water is a cheese and the wolf bursts in the attempt to drink up the water to get at the cheese; the Zulu tale of the hyena that drops the bone to go after the moon reflection in the water; the Gascon tale of the peasant watering his ass on a moonlight night. A cloud obscures the moon, and the peasant, thinking the ass has drunk the moon, kills the beast to recover the moon; the Turkish tale of the Khoja Nasru-'d-Din who thinks the moon has fallen into the well and gets a rope and chain with which to pull it out. In his efforts the rope breaks, and he falls back, but seeing the moon in the sky, praises Allah that the moon is safe; the Scotch tale of the wolf fishing with his tail for the moon reflection;

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