Depends on how far back in time you consider to be ancient. Most of the dishes we eat today are derived from earlier days. The French, Italian, Spanish etc. kitchens are all grown out of the day-to-day foods eaten in the regions, provinces etc. The most famous dishes of to day have very humble beginnings, peasant food if we'd like to call it that.

To take one dish that is found around the world to day, the famous Pizza started of as the poor mans food. Bread covered with olive oil, herbs and cheese and from there it slowly evolved.

I don't know the absolute validity of the claims but the famous Pizza Margherita is said to have originated in 1889 as a special pizza made to Queen Margherita. Here's an article about it in more detail: http://www.italymagazine.com/featured-story/pizza-margherita-history-and-recipe

Food has also evolved through out the ages. Back in the day we didn't have black pepper in every country, the europeans brought among other things the chilli to Asia and the potato and tomatoes to Europe from the new world. So pinpointing what is an original dish is hard as they've lived and evolved throughout the ages. The humble bagel traces it roots to the 1600s, more about this here.

Lentils have been found in excavations dating back to approx. 10 000 years ago and lentils soup is mentioned in the bible Genesis 25:30-34. And if I remember correctly snails with garlic was eaten by the romans and it's a dish still popular and available in any french or italian restaurant.