One theory has it that the bow developed from the increasingly long plectra that were used in lyre strumming from earlist times. Certainly the earlist iconographical evidence for stringed instruments being played with a bow depict lyres (crwth / crowd etc.) rather than fiddles, which came about when the bow was later applied to lute type instruments.

As a bowed instrument, the lyre existed in Northern-Europe until comparatively recent times in the form of the Welsh crwth and the various talharp / jouhikko instruments that would appear to be undergoing something of a revival pesently.

For more on the crwth click HERE