Today is St Crispin's Day, on which a retreating and outnumbered English army under Henry V defeated a much larger force of French nobility at Agincourt. The English victory was down to their lead in the arms race - in particular, their longbows, which cut the superior French numbers to pieces.
The two-fingered 'fuck off' salute is said to have arisen from the fact that the French would cut three fingers from the right hand of captured bowmen. The two fingers are supposed to have been raised to show that those raising them could still wield their bows.
Despite its later adoption as one of the central myths of the English nation, Agincourt was more a battle between competing nobles over lands in northern France than it was a conflict between two nations. And - some consolation for ordinary English and French alike - at least those who sent the armies to war were doing the fighting themselves. In all, more than 7,000 French knights and gentlemen and 120 of their lords perished on the field of battle at Agincourt.
We few, we happy few, we band of brothers;
For he today that sheds his blood with me
Shall be my brother; be he ne'er so vile,
This day shall gentle his condition:
And gentlemen in England, now a bed,
Shall think themselves accurs'd they were not here;
And hold their manhoods cheap whiles any speaks
That fought with us upon St Crispin's Day.