Who is the "Jack" in Cards?

Well, we know what a King and a Queen is, but what is a Jack? A prince? A servant? A nobleman? A peasant? Who is it? - Jinx

This might help

Ok, who are the Kings and Queens in a French deck?

Both from wikipedia.

You may find it interesting to note that in the society of the time, a knave was actually pretty high up in the food chain. Definitely way above a peasant. As agents of the lord and lady of the manor, they could speak for them in dealings with lesser individuals and so wielded a lot of power.

And the knaves spent all their time bossing around the 10s.

Except in the kingdom of Pinochle.

What, even scurvy knaves?

Note that in tarot decks there are 4 court cards - King, Queen, Knight and Page in the most common ones. Early playing card decks did not have the same set of court cards as modern decks, and they varied, although 3 court cards per suit was standard. Wiki on the tarot deck, which was originally used for game playing, rather than divination:

King, Knight and Page would probably have been a common set of court cards in early playing card decks. Later evolution standardized on King, Queen and Knave or Jack.