As said above, it started with the Magna Carta in 1215, when King John was forced to acquiesce to the nobility, and set up a council (the Magna Carta formalised this arrangement - since William the Conqueror there had been an informal council of local chiefs who would advise the King).
From there Parliament began to develop, slowly taking powers away from the monarch, and gaining more power for itself. The Commons began to meet separately from the Lords in 1341.
The supremacy of Parliament was pretty much confirmed by the Civil War, and when Charles II returned from exile, from then onwards every King and Queen was a constitutional monarch, restrained in their actions by Parliament.
Its main roles are:
Parliament
1327
Edward I established the Parliament in England.
King Charles I of England
Charles the first launched a war on Parliament. Parliment won. A law was passed that the king/queen would stay but Parliament would be the premier political institution in England
Parliament of england
For all practical purposes, Robert Walpole was the first prime minister of England. When Parliament elected King George I, the king, parliament elected Robert Walpole, Prime Minister. King George stayed in Europe. He let Walpole run England. Since England does not have a written constitution as does the United States, there is no particular point where England said, "We now have a modern prime minister."
Parliament.
City of London - elections to the Parliament of England - ended in 1950.
City of London - elections to the Parliament of England - was created in 1298.
Parliament was the ruler of England. But 4 the ruler of England during the Revolutionary War it was King George III.
Great Council