There is a legend that since bowmen captured by French forces sometimes had their bow-drawing fingers cut off, the English and Welsh longbowmen at the Battle of Agincourt, which an English army won in 1415, employed the now insulting "V" sign to taunt the French, to show that they had the necessary fingers and they were in full working order.
Unlike the peace sign which has the palm outwards, towards the message receiver, the insulting sign has the palm inwards, towards the message sender. Used in Britain, Ireland, Australia and New Zealand, the sign is in some circumstances analogous to the middle-finger gesture that is more common in the United States.
What is the earliest known date for the legend?