I'd guess because it's the approximate age of the recorded English common law, which is the main basis of the American legal tradition.
https://en.wikipedia.org/wiki/English_law#Common_law
(not that that is the first court or legal system in human history)
I'd guess because it's the approximate age of the recorded English common law, which is the main basis of the American legal tradition.
https://en.wikipedia.org/wiki/English_law#Common_law
(not that that is the first court or legal system in human history)