Between his great victory at the battle of Lewes in May 1264 and his defeat and death at the battle of Evesham in August 1265, de Montfort ruled England in the name of the Provisions, wielding power not seen again until the days of Oliver Cromwell.

He supported his regime by summoning knights and burgesses to parliament, and by claiming he was rescuing the English from the domination of foreigners. This was an important period in the development of parliament and of English national feeling.

It is exciting, therefore, to discover that an old source for this extraordinary period has been completely misunderstood, and tells us far more about its controversies than has previously been recognised.

The source is a chronicle called the Flores Historiarum, the Flowers of History. All previous commentators have assumed that this was written at St Albans Abbey, being a continuation of the work of its great historian Matthew Paris, who died in 1259. Yet the section between 1263 and 1265 has no references to St Albans, while it does mention Pershore Abbey in Worcestershire and its abbot, Eleurius.

It also has much about the surrounding area, and overlaps in terms of phraseology with another chronicle (only surviving in fragmentary later copy), which was certainly written at Pershore. It is almost certain, therefore, that the Flores Historiatrum comes from Pershore. What is also clear is that it gives an absolutely contemporary view of events. Indeed, the account of the battle of Lewes was composed, and the text we have was actually written up, before de Montfort’s destruction next year at the battle of Evesham.

This is therefore a view of his regime unspoilt by the usual hindsight.

What is striking, when the true nature of the Pershore Flores is appreciated, is the remarkably balanced view it offers of this revolutionary period. The chronicle certainly supports de Montfort’s cause. At Lewes, under his leadership, the barons are fighting "for the country united in faith and will".

Yet, on the other hand, Lewes is described as an event of "calamity and misery", witnessing "sedition and war between the citizens of one land". Elsewhere, while the chronicle describes de Montfort as "most noble and most excellent in warlike things", it also sympathises with the predicament of the king, and in a remarkable passage, lauds the energy and courage of his queen, Eleanor of Provence.

More like this

In all this, the chronicle almost certainly reflects the views of its probable patron, Eleurius, the abbot of Pershore. Eleurius was a monk from Fécamp Abbey in Normandy who had come to England in the 1230s to look after its English properties.

On the one hand, he was closely associated with de Montfort, particularly through the latter’s Norman friends. But, entering the royal service, and rising to be a chief official of the exchequer, he was also a tried and trusted servant of the king and queen. The chronicle represents his efforts to steer a middle path through the turmoil of the 1260s.

Those efforts were not entirely appreciated at Pershore. Eleurius resigned as abbot in October 1264. Shortly afterwards, the account of the battle Lewes was altered by a Pershore monk to stress the God-given nature of de Montfort’s victory.

Since such pro-de Montfort doctoring would never have happened after the battle of Evesham, this is one of the proofs that the text of the chronicle was written very soon after the events it describes.

The chronicle’s staunch support for de Montfort was soon, however, to prove equally unpalatable. In the late 1260s Pershore gave its copy of the Flores (it probably had others) to the very royalist Westminster Abbey. The Abbey could not stomach the account of Lewes and erased the most provocative of the passages hailing de Montfort’s victory.

So the balanced account of de Montfort’s regime in the Pershore Flores, as conceived by Abbot Eleurius, failed to please the extremes on both sides. This is, in itself, a remarkable testimony to the tensions that pulled England apart in this tumultuous period.

This blog highlights research by David Carpenter that appears in the journal English Historical Review. For a limited time, you can read the full text of Professor Carpenter's article for the journal for free.