Petah are they going to bomb the house

Peter, my friend posted this in the group chat and I feel out of the loop..

I don't get it

Petah

Petah, this is the first "medieval" meme I don't understand

Petah! Why is everyone in Illinois mad at Canada?

Peter what does this joke mean?

Sorry if it's obvious

???

Petah? Am I stupid?

Peter please explain