HENRY III AND THE MAGNA CARTA THAT MATTERED

King John's sealing of a charter at Runnymede in 1215 is one of the most feted moments of the Middle Ages. Yet, writes David Carpenter, it was the charter issued by his son 10 years later that became fundamental to England's history

- David Carpenter

This February marks the 800th anniversary of Magna Carta. But wait - surely we already commemorated that milestone in 2015? Certainly, on 15 June that year, the Queen, the Duke of Edinburgh, the archbishop of Canterbury, prime minister David Cameron and assorted dignitaries gathered at Runnymede. At the meadow by the Thames between Windsor and Staines, they celebrated the charter King John had sealed there exactly 800 years earlier.

That document, sealed under duress from rebel barons and famously subjecting the king to the law and promising justice to all, is widely lauded today as a milestone in the establishment of English law. Yet the fact is that, in the centuries after 1215, the term Magna Carta was hardly ever used for John's document. Rather, that was the name given to the charter issued nearly a decade later by King John's son, Henry III, at Westminster on 11 February 1225.

Although Henry's charter was based on his father's, the earlier iteration was usually called simply the 'Charter of Runnymede'. So when, in 1297 and 1300, Henry's son Edward I confirmed Magna Carta, he meant the charter of 1225 - and the same was true of all later confirmations. Indeed, though most of its provisions have since been repealed, those chapters that remain on the statute book of the UK today are from the 1225 version. So how did the Charter of Runnymede in 1215 become Magna Carta in 1225?

Abandoned promises