It was in 1265, 750 years ago this month, that a parliament convened by English rebel leader Simon de Montfort, took place in Westminster Hall (exterior pictured below).

The French-born De Montfort, who led a group of rebel barons, was riding high after defeating King Henry III at the Battle of Lewes on 14th May, 1264. While he ruled in the king’s name through a council – having captured both the king and his son Prince Edward, the monarch was no more than a figurehead. De Montfort was effectively the man in charge.

In a bid to solidify his hold on the country, he summoned not only the barons and clergy but knights representing counties to a parliament along with – for the first time – representatives from major towns and boroughs like York, Lincoln and the Cinque Ports (the representatives were known as burgesses).

It’s this latter move which led this three month-long parliament to be described as the first English parliament and which has led de Montfort to be described by some as the founder of the House of Commons.

Presided over by King Henry III, the parliament was held in Westminster Hall in London – a city loyal to de Montfort’s cause. It dealt with a range of political matters including the enforcement of a series of government reforms known as the Provisions of Westminster which had been aimed at strengthening baronial rights and the role of courts.

Prince Edward (later King Edward I) managed to escape from de Montfort’s clutches later in 1265 and led forces against de Montfort. The rebel leader was killed at the Battle of Evesham on 4th August, 1265.

The UK Parliament is marking the 750th anniversary of De Montfort’s Parliament with a series of events (along with the 800th anniversary of the sealing of the Magna Carta) – check out www.parliament.uk/2015 for more.