If I recall correctly the *caste* system for the Minors is as follows:
1. Swords: nobility. Those who can afford and use (i.e., fight with) expensive weaponry.
2. Cups: priesthood. The people of religion who seek to fill themselves with noble truth.
3. Wands: merchants. They have luxury of being able to travel (wand as walking stick) and the pragmatism to defend themselves (wand as weapon... not a noble weapon of the nobility, though.)
4. Pentacles: commoners. Those who are concerned with the everyday needs of life, like food, money, and the work they do to get food/money.
I think I watched a video on YouTube where this was explained, and if I can find that video again, I'll try to link it here.