Bouillabaise! Versions of it has been consumed on the French and Italian Med. Coast since Roman times. (Remember, lots of Italians lived on the french coast. )
If not before.
Simple: take the fish and seafood that is left over / cheapest, and cook it with local herbs and spices.
The Tomato from south America revolutionised European cooking. The Potato too.
Hamburger? Yes, that is what you call it. We do not. Untill the US food invasion.
Hackebøf, hackebiff, pannbiff, frikadellen, and so on, are what we call it, we who speak another tongue!
In Sweden we have been eating Pannbiff for centuries, and the rest of Europe too.
Finely cut/ground beef or beef/pork mix, salt, pepper. Make a ball, flatten it, panfry.
Old dish.
Older than when the Vikings discovered America.
After the slaughter, you have lots of small pieces of meat offcuts.
You either make sausages, or pate, or meat patties.
Also, tougher meat benefits from being ground/ cut into small pieces.
But we eat it with steamed potatoes and some kind of sauce.
I do think it was put between bread in the US, unless ot was Earl of Sandwich.
Wiki says that is was the Germans in Germany that put the pattie between bread.
They have invented lots in Germany.