Moon is made of green cheese

A metaphor for a preposterous impossibility as in, it is like believing that the moon is made of green cheese. Or, one might say after hearing a ridiculous statement, and the moon is made of green cheese. The first citation is John Frith Epistle to a Christian Reader (1529) “They would make me believe that the moon was made of green cheese.” It also appears in John Heywood Proverbs (1546) which indicates that it is perhaps much older than the 16th century.