Origin of phrase 'come on'
The origin of "come on" seems hard to find, but I can find it in English here (1691): The Miser: a comedy in five acts and in prose.
It says:
Come on, Musicianers, strike up, Hey: Here forsooth, here's your health; and would I might ne're go out of this place.
Early uses of "come on" seem to only be to get moving.
In Dutch, it has appeared during the same time (1695), in the form of Komaan: De Knorrepot, of de gestoorde Doctor. (It says "Komaan , myo Heer , ik ben gereed te tekenen" which means something like "Come on, My Lord, I am ready to sign".)
I cannot find any uses of "come on" earlier than that.