Would a French person care if you said 'Agincourt' to them?

Short answer : No as long as you don't use it to insult them.

Long answer :

If you say Agincourt, it's fine. Why would it bother us ?

Firstly, the battle is called bataille d'Azincourt in french and Agincourt is an other town where no battle has taken place (hundreds of kilometres from Azincourt).

Secondly, Azincourt is also a town and I doubt people will become aggressive if you say the name of a town.

If you say "We beat you in Azincourt. You are weak, etc...", the person will think you have a problem with your mind and the person will be right about it. Firstly because you weren't there and the person was not ther either and secondly because the french won the hundred years war and thirdly because this is only an excuse to have an argument and has nothing to with the battle.

But generally speaking nobody cares about this battle. You will not be attacked for just saying the name Azincourt. However you will probably be treated badly if you start insulting people and saying they are worthless using this battle as an argument.

It's same same thing than with William the conqueror. If a french person just says Guillaume le Conquérant to an english, the english person will not care. But if th french person says "Guillaume kicked your asses, you're worthless", it's just an excuse to have an argument.

Hopefully most of the english and french people are not this stupid.

Some people do have long memories.

And don't call me, "Shirley". :-)