Here are the rules:

1. Four people at the table: you and three others.
2. They can be living or dead.
3. They have to be or have been a real person. No cartoon or fictional characters.
4. They can be famous, infamous or just an ordinary person.
5. Introductions are not required: everyone will be familiar with the others at the table.
6. If you want to have a conversation, they can only speak in languages they know or knew at the time they were alive.
7. Translators are not extras. If you need a translator, they would need to occupy one of the three seats. That means, for example, that if you choose Moses and Socrates, the third person would need to be fluent in English, ancient Hebrew and ancient Greek so that everyone can participate the discussion. For that reason, a translator does not need to be famous but can be an ordinary person who's multi-lingual. (No one, not even Jesus, gets a free pass for being conversant in every known language.)
8. It's entirely up to you to divulge why you selected the people you did and what, if anything, you hope to accomplish by bringing them together. Just know that the past can not be undone, i.e., sitting Jesus and Hitler down together will not undo the millions of deaths the Nazis inflicted.
9. Lunch lasts two hours. You're picking up the tab. Be sure to tip your wait staff.

This is entirely hypothetical. Please keep any witticisms and repartee civil.