An Etymological Dictionary of the German Language/Annotated/je
je, adverb, older ie (which in the 17th century was supplanted by je, recorded at a still earlier period), ‘always, ever,’ from Middle High German ie, ‘at all times, always (of the past and present), the (with compars., distributives, &c.), at any (one) time,’ Old High German io, eo, ‘always, at any (one) time.’ The earliest Old High German form eo is based on *êo, aiw (compare See, Schnee, and wie); compare Gothic aiw, ‘at any time,’ Old Saxon êo, Anglo-Saxon â, ‘always’ (English aye, from Old Icelandic ei, ‘always’). Gothic aiw is an oblique case of the substantive aiws, ‘time, eternity,’ and because in Gothic only the combination of aiw with the negative ni occurs, it is probable that ni aiw (see nie), ‘never’ (‘not for all eternity’), is the oldest, and that the positive meaning, Old High German eo, ‘always,’ was obtained à posteriori; yet compare Greek αἰεί, ‘always,’ allied to αἰών, and see ewig and the following words.