This day in history:
The Magna Carter (great charter) was signed by King John at Runnymede in 1215.
The most memorable part of the Magna Carter is the declaration that all free men have the right of justice and free trial (the basis of many courts today). Unfortunately, at the time, the peasants were ruled by landowners and weren't considered free. Many of the clauses were also used in the United States Bill of Rights.
Terry Jones (Monty Python) gives a great animated outline of the events surrounding the Magna Carter below.