c. 1300, "an inquest, a judicial inquiry;" early 14c., "a search for something, the act of seeking, pursuit" (especially in reference to hounds seeking game in the hunt), from Old French queste "search, quest, chase, hunt, pursuit; inquest, inquiry" (12c., Modern French quête), properly "the act of seeking," and directly from Medieval Latin questa "search, inquiry," alteration of Latin quaesitus (fem. quaesita) "sought-out, select," past participle of quaerere "seek, gain, ask" (see query (n.)).
The medieval romance sense of "adventure undertaken by a knight" (especially the search for the Grail) is attested from late 14c. Chaucer has questmonger (late 14c.), "one who profits from an unjust action at law."
mid-14c., questen, "to seek game, hunt" (in reference to dogs, etc.), from quest (n.) and from Old French quester "to search, hunt," from queste (n.). Related: Quested; questing. Of persons, in the general sense of "go in search, make inquiry," by 1620s. Of hunting dogs, "to bark, bay," as when on the scent of game, mid-14c., hence the questing beast, fabulous animal in Arthurian romances, which was so-called according to Malory for the sound it made:
I am the knyght that folowyth the glatysaunte beste, that is in Englysh to sey the questynge beste, for the beste quested in the bealy with suche a noyse as hit had bene a thirty couple of howndis. ["Le Morte Darthur"]