What is the name of the medieval parliament in England that grew in power over time?

The story behind the answer

It was the representative assembly that steadily shifted power away from the monarch, especially by controlling taxation—the “power of the purse.” Growing out of the king’s council and strengthened by Magna Carta (1215), it took clearer form with Edward I’s Model Parliament (1295), which included nobles, clergy, knights, and burgesses, giving towns and shires a political voice.

Over time, it developed into two chambers—the Lords and the Commons—and became central to English governance, asserting decisive authority during the 17th century conflicts and the 1689 Bill of Rights. By contrast, the Great Council and Curia Regis were primarily royal advisory or judicial bodies, and the Witan belonged to the earlier Anglo-Saxon period.