The reign of Henry III (1216-72) was largely one of peace, both domestically and internationally. Relations between king and barons, in the age of Magna Carta, were far improved from the days of King John, as were relations with France. Henry was also known as a devout and faithful king, rebuilding Westminster Abbey in honour of his patron, St Edward the Confessor. By the 1250s, however, his rule was blighted by financial difficulties and unpopular policies, particularly his expensive ambition of conquering the Kingdom of Sicily, and his patronage of his unpopular half-brothers, the Lusignans.

Things came to a head in 1258, when a cadre of barons marched on the king’s hall at Westminster and seized the reins of power. They set up a council to govern in the king’s stead with the help of parliament, henceforth to be held three times a year come what may. The new regime implemented a series of central and local reforms that came to be known as the Provisions of Oxford. In the early 1260s, however, Henry recovered power. In response, in 1263, Simon de Montfort earl of Leicester led a violent campaign to reimpose the Provisions by force. This was the outbreak of civil war, which was to last until 1267.

The period is sometimes referred to as the Second Barons’ War, the First being that fought between King John and his barons, which ended in 1217 with the Battle of Sandwich, but this is misleading. The principals at stake were very different, with the Montfortians seeking to overhaul the very system of government in a way that was utterly radical. The conflict also involved men and women of every status across the kingdom: not only barons but queens and countesses, knights and peasants – as well as the many bishops, monks and friars who supported the Montfortian cause. For these reasons the era is now generally referred to as ‘England’s First Revolution.’

Hostilities reached a new peak in the early months of 1264. The theatre of conflict focused on the south-east, a vital region as the royalists would seek to bring in reinforcements from France. The Montfortians held London and Dover Castle, while the royalists held Rochester Castle (the Montfortian siege of Rochester in April 1264 was unsuccessful). The royalists moved from Rochester to Tonbridge, Battle and then Winchelsea, enclosing the Montfortian garrison at Dover. In response, Simon de Montfort sought to draw the royalists away from Dover by heading into Sussex. He brought his force to his manor of Fletching (Sussex) by 6 May, and there entered into negotiations with the king, based at Lewes, although it is not clear that either side expected talks to succeed. On 13 May, the Montfortians moved to the northern outskirts of Lewes, between Offham and Hamsey.

The following day, 14 May, saw an astounding victory for the Montfortians, with the king and other members of the royal family taken prisoner. The victory allowed the Montfortians to establish a new revolutionary government, with a council of nine ruling the kingdom, aided by parliament. The regime was finally brought down at the Battle of Evesham, 4 August 1265.

There is uncertainty as to exactly where between the top of Offham Hill and the medieval town the battle was actually fought. Thus it is unclear how much of the battlefield actually remains undeveloped. While the top of Offam Hill and the slopes to the south and south-west remain as agricultural land, the town of Lewes has spread far beyond its medieval boundaries and thus modern housing covers much of the eastern and lower slopes of the hill. Access to Offam Hill is possible via several footpaths, while both the ruins of the priory and (for a fee) the castle are also accessible.

Following the Barons victory at Lewes, King Henry and Prince Edward were held by de Montfort who governed in their name. But ultimately the victory did not prove decisive, for de Montfort was to loose the support of many of the disaffected Barons. Edward eventually escaped and raised forces against de Montfort culminating in the battle of Evesham.

There is uncertainty as to exactly where between the top of Offham Hill and the medieval town the battle was actually fought. Thus it is unclear how much of the battlefield actually remains undeveloped. While the top of Offam Hill and the slopes to the south and south-west remain as agricultural land, the town of Lewes has spread far beyond its medieval boundaries and thus modern housing covers much of the eastern and lower slopes of the hill. Access to Offam Hill is possible via several footpaths, while both the ruins of the priory and (for a fee) the castle are also accessible.
 

• Historic England Battlefields Register CLICK HERE
• Historic England battlefield report for Battle of Lewes 1264