I believe it was their first two fingers, as they are what you draw a bow with. This was the origin of the v's-up. I believe that is also incorrect, that is one word which has been around an incredibly long time - long enough that no one knows the true etymology of it. It was seen in writing from before 1500 in a poem composed in both latin and english reading: Flen, flyys, and freris, // Fleas, flies and friars, Non sunt in coeli, quia, // They are not in heaven, since gxddbov xxkxzt pg ifmk The last line is in code because it's considered offensive even then, it is put through a rotation of 1. When decoded it yields: fvccant vvivys of heli // They f-word wives of Ely (a nearby town) - note that 'V' was used for both U and V, and 'VV' was used for W in those dayes of yore. Wiktionary is excellent for etymology.