Is it farther or further?
1540s, from Middle French paragon "a model, pattern of excellence" (15c., Modern French parangon), from Italian paragone, originally "touchstone to test gold" (early 14c.), from paragonare "to test on a touchstone, compare," from Greek parakonan "to sharpen, whet," from para- "on the side" (see para- (1)) + akone "whetstone," from PIE root *ak- "sharp, pointed" (see acrid).
Mark Sherman. IEEE Software (Nov 1991).