An Etymological Dictionary of the German Language/schon

by Friedrich Kluge

schon, adv., ‘already, even,’ from MidHG. schôn, schône, adv., from schœne, adj., ‘beautiful'; the ModHG. sense occurs very seldom in MidHG., and is entirely unknown to the courtly poets; MidHG. schône, OHG. scôno, ‘in a handsome manner,’ are formed without the mutation of schön; comp. fast from fest.