E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Fools Paradise.
Unlawful pleasure, illicit love, vain hopes. Thus, in Romeo and Juliet, the Nurse says to Romeo, If ye should lead her [Juliet] into a fools paradise, it were a gross . behaviour. The old schoolmen said there were three places where persons not good enough for paradise were admitted: (1) The limbus patrum, for those good men who had died before the death of the Redeemer; (2) The limbus infantum or paradise of unbaptised infants; and (3) The limbus fatuorum or paradise of idiots and others who were non compos mentis. (See LIMBO.)