recondite knowledge

See: secret
References in classic literature ?
Others of Lyly's affectations are rhetorical questions, hosts of allusions to classical history, and literature, and an unfailing succession of similes from all the recondite knowledge that he can command, especially from the fantastic collection of fables which, coming down through the Middle Ages from the Roman writer Pliny, went at that time by the name of natural history and which we have already encountered in the medieval Bestiaries.
Susanna Akerman's "The Gothic Kabbala" is a bricolage of commentary and recondite knowledge about cabbalistic, Rosicrucian and other apocalyptic and mystical directions, mainly in Scandinavia in the seventeenth century: a long way from 1492, or even from its aftermath.