Simon de Montfort and the Birth of Parliament, 1258-1265

Henry III and the Sicilian Business

Magna Carta was supposed to settle the question of royal power. By the 1250s, it was settling nothing. Henry III, son of King John, had reigned since 1216 and inherited his father’s habit of overreaching. His most damaging mistake was the ‘Sicilian Business’ — in 1254 he agreed with the Pope that his second son Edmund would become king of Sicily, a kingdom Henry would have to conquer first. Henry promised to fund a vast military campaign, then asked his barons to pay for it.

The barons refused. They were already angry that Henry surrounded himself with foreign favourites, especially his French half-brothers from Poitou, who held lucrative offices and lands. They had watched Henry’s government fail to enforce justice locally and ignore the spirit of Magna Carta. The Sicilian Business was the breaking point.

The Provisions of Oxford, 1258

In April 1258, seven barons stormed into Westminster armed and demanded reform. At a parliament in Oxford that June, they forced Henry to accept the Provisions of Oxford, sometimes called England’s first written constitution. Under the Provisions, a 15-member council of barons supervised the king. A parliament would meet three times a year. Royal sheriffs would answer to local communities, not just to the king.

The most prominent reformer was Simon de Montfort, Earl of Leicester. Born in France around 1208, he had married Henry’s sister Eleanor in 1238 and built a power base in the English Midlands. De Montfort was charismatic, ruthless, and committed to legal reform. He was also — ironically, given the foreign-favourites complaint — himself a Frenchman by birth.

Civil War and the Battle of Lewes, 1264

Henry chafed under the Provisions. In 1261 he asked the Pope to release him from his oath, and reasserted royal authority. The barons split. By 1263 the country was in open civil war, the Second Barons’ War. At the Battle of Lewes in May 1264, de Montfort decisively defeated the royal army and captured both King Henry III and his son Prince Edward. For the next fifteen months, de Montfort effectively ruled England.

The Parliament of January 1265

De Montfort needed broad support against royalist holdouts. In January 1265, he summoned the most innovative parliament England had ever seen. Alongside the usual barons and bishops, he called two knights from every shire and two burgesses from each major town. For the first time, commoners — townspeople and lesser landholders — sat in a national assembly.

The Battle of Evesham, 1265

Prince Edward escaped from house arrest in May 1265 and rallied royalist forces. On 4 August 1265, at Evesham in Worcestershire, Edward’s army caught de Montfort’s smaller force. The earl was killed; his body was mutilated — head, hands, feet and genitals cut off — in a deliberate humiliation. The reform movement collapsed; Henry III was restored to full power; many of de Montfort’s lands were confiscated.

The Long-Term Impact

In the short term, the reform movement failed. But Edward I, when he became king in 1272, kept what worked. His ‘Model Parliament’ of 1295 included two knights from every shire and two burgesses from every borough — exactly de Montfort’s 1265 format. The two-chamber Parliament we know today, with House of Lords and House of Commons, evolved from these summonses. By the fourteenth century, the practice had hardened into custom.