From where do we get tartar sauce?

Tartare sauce (or Tartar sauce - US alternate spelling) is a thick white sauce made from mayonnaise and finely chopped pickled cucumber, capers, onions (or chives), and fresh parsley. Chopped hard-boiled eggs, olives, and horseradish are sometimes added, and dijon mustard is often used as an emulsifier. It is frequently used to season fried seafood dishes. It can also be made by mixing commercially produced relish and mayonnaise. Vinegar can be added for a sharper flavor. The sauce is typically of a rough consistency.

https://en.wikipedia.org/wiki/Tartar_sauce

Yes, but what culture first came up with it?

as per the link I attached it said in that link it was invented by the French.

Most of us either buy it in the supermarket or mix our own version of mayonnaise, pickles, horseradish, and other secret ingredients.

Originally, tartar sauce was made in France.

"The history of tartar sauce is a bit tangled. It appears to have been developed by the French as a sauce for steak tartare, a famous French dish with thinly chopped raw steak, and at some point, the name was changed to “tartar.” In some regions of the world, people continue to use the French spelling. In any case, tartar sauce appears to date to the 1800s, although similar sauces have been made as far back as the 1600s."
http://www.wisegeek.com/what-is-tartar-sauce.htm

The origins of "steak tartare" would answer a different question.

In the UK, spelled 'tartare', and most commonly found without onions or chives. Gherkins and capers are essential. I can only remember once finding it with onion in it - a great disappointment as I hate onion and love tartare sauce.

This is strange because there are people called the Tartars who live mostly in Eastern Europe, but they did not create tartar sauce.

https://en.wikipedia.org/wiki/Tatars

The French name for steak tartare comes from the Tatars (PC spelling now) who allegedly put meat under their saddles to tenderise it. (Might work - can't see it being very comfortable for the horse.) When the French took to a dish of raw beef or horse, they gave it the name of these people. The sauce took its name from the beef dish. Tenuous connections all round, but all we've got.
https://en.wikipedia.org/wiki/Steak_tartare
Eating real Steak Tartare is not recommended unless you are absolutely sure of the hygiene in the kitchen, the butchers and the abatoir. And sure that it hasn't been transported under a saddle.

There's some more interesting comments about the steak tartare on:
https://en.wikipedia.org/wiki/Talk:Steak_tartare
And about the sauce on:
https://en.wikipedia.org/wiki/Talk:Tartar_sauce