Is it farther or further?
mid-12c., from Old French tresor "treasury, treasure" (11c.), from Gallo-Romance *tresaurus, from Latin thesaurus "treasury, treasure" (cf. Spanish, Italian tesoro), from Greek thesauros "store, treasure, treasure house" (see thesaurus). Replaced Old English goldhord. General sense of "anything valued" is recorded from c.1200. Treasure hunt is first recorded 1913. For treasure trove, see trove.
late 14c., "to amass treasure; to store up for the future," also figurative, from treasure (n.). Related: Treasured; treasuring.