Riddle #5

I don't know if anyone reads the riddles I post on this blog, but I will continue to post riddles anyway. Here goes:

A dozen royals gathered round
Entertained by 2 who clowned
Each king had their servents 10
Though none of them were also men
The lowest servant sometimes might
Defeat the king in a fair fight
A weapon stout, a priceless jewel,
The beat of life, a gardeners tool.

What is this poem talking about?