The Greek author Plutarch wrote one of the great classics of ancient literature, Parallel Lives, brief biographies of notable Greeks and Romans. Plutarch was a brilliant man but, like most intellectuals, had a few crackpot ideas floating around in his mind.
Take this one, for example: he thought a female cat produced one cat in her first litter, two in her second, and so on until she reached the magic number of twenty-eight, at which time she ceased bearing kittens. Well, no female cat ever bore twenty-eight in one litter, of course. Plutarch based that number on the old connection of cats with the moon: there are twenty-eight days in a lunar month, so Plutarch figured a female should bear twenty-eight kittens. As I said, a crackpot idea, but an amusing one.