When was the English Parliament formed?

The formation of the English Parliament is most accurately associated with the year 1265. This year marks the convening of what is often regarded as the first representative Parliament under Simon de Montfort, where commoners, along with nobles, were invited to discuss and make decisions regarding governance. This event represented a critical evolution in English political structure, as it began to include more diverse representation, moving from an assembly primarily comprised of the nobility to one that included members of the emerging middle class or commoners.

The earlier date of 1215 is significant for the signing of the Magna Carta, a foundational document that limited the powers of the king and laid the groundwork for future constitutional governance. However, the actual parliamentary system that included representatives from various classes did not emerge until later. The date of 1300 does not correspond with a notable development in the establishment of Parliament; by this time, the institution was already developing but had not yet reached the stage recognized as official. Lastly, the year 1400 falls outside the scope of the initial formation phase when the Parliament began to take its definitive shape as a political body participating in governance.