Do you know the correct date of Magna Carta? Here’s why you might be wrong

But according to Professor David Carpenter, one of the world’s leading authorities on Magna Carta, we might have been commemorating the wrong occasion all along. Speaking on the HistoryExtra podcast, Carpenter explains that at the time, people didn’t see King John’s 1215 charter as the Magna Carta at all.

“For people in the 13th century and beyond, John's charter was not regarded as Magna Carta," said Carpenter. Instead, they saw it as "the Charter of Runnymede.”

So if 1215 wasn’t the defining moment, what was? The answer, Carpenter argues, is 11 February 1225 – the date when John’s son, Henry III, issued the final, definitive Magna Carta. “And in that sense, therefore, the 800th anniversary of Magna Carta is 11 February 2025,” Carpenter explains.

• On the podcast | Are we celebrating the wrong Magna Carta?

What was Magna Carta actually about?

The 1215 charter, often hailed as a cornerstone of constitutional law, was essentially a peace treaty. It was a response to the significant grievances of England’s barons, who were furious at King John’s military failures, heavy taxation, and abuses of power.

The charter established a crucial principle: the king was subject to the law. But unlike modern declarations of rights, Magna Carta wasn’t a sweeping statement of liberty. It was a highly practical document, laying out specific limits on royal power. It regulated taxation, feudal inheritance, and legal procedures, while also talking about more prosaic matters such as fish weirs. One of its most famous clauses, still quoted today, declared:

"To no one will we sell, to no one deny or delay right or justice."

Yet for all its significance, the 1215 Magna Carta failed almost immediately.

Why is 1225 important in Magna Carta’s story?

King John had no intention of honouring Magna Carta, and within months, he persuaded Pope Innocent III to annul it. Civil war erupted, and in desperation, the rebel barons invited Prince Louis of France to take the English throne.

Everything changed when John died in October 1216. His nine-year-old son, Henry III, inherited the throne, but his supporters needed to find a way to stabilise the kingdom. Their solution? Reissuing Magna Carta.

• Read more | Henry III and the Magna Carta that mattered

“In November 1216, from Bristol, Henry issues a new version of the charter,” Carpenter explains. It was a politically strategic move that intended to win back support from barons who had sided with Louis. A further revision followed in 1217, alongside a new Charter of the Forest, which regulated royal forests – a major grievance for landowners.

It was at this point that Magna Carta got its famous name. “We've got to remember that John's [1215] charter is the Charter of Runnymede,” says Carpenter. But after 1217, when the Charter of the Forest was introduced, royal clerks needed a way to distinguish between the two. “So they decide to give it the term ‘Magna Carta’. And all that means is Great Charter.”

How was the 1225 Magna Carta different?

The 1225 version of Magna Carta wasn’t just another reissue – it was qualitatively different from 1215. The key change was that it was no longer extracted from the king by force. Instead, Henry III freely granted it in exchange for taxation.

“There was growing unease over the legitimacy of the earlier versions,” Carpenter explains. William Brewer, a former minister of King John, questioned their legality in 1223, arguing: “The charters of Henry III should not be obeyed. They have no validity because they've been extracted by force.”

The 1225 version removed any doubt by explicitly stating that it was given in return for taxation. “And so no one anymore can say the king has been forced to do it. He's done it freely,” says Carpenter. This made 1225 the final and definitive version of Magna Carta.

Crucially, the 1225 Magna Carta also excluded the most radical part of the 1215 charter – the security clause. The original 1215 charter had contained a revolutionary provision allowing 25 barons to enforce the agreement, even by seizing royal property. It was, in essence, a recipe for civil war.

Because of these changes, “no later king really felt the need to issue another version,” Carpenter noted. Whenever later kings confirmed Magna Carta, they confirmed the 1225 version – not John's 1215 charter. “Even in the 17th century, when the great lawyer Edward Coke dusted down Magna Carta as a bastion against Stuart tyranny, what did he appeal to? It was still the 1225 charter,” says Carpenter.

How did 1215 take over?

So why does everyone focus on 1215 instead of 1225?

The answer lies in the 18th century, with Sir William Blackstone, an influential English lawyer. Blackstone was the first person to print all the different versions of Magna Carta together, showing how they had evolved. His decision to label the 1215 document as the Magna Carta stuck.

“He took an absolutely crucial decision,” Carpenter explained. “He called John's charter of 1215, not the Charter of Runnymede – he called it Magna Carta.”

“Such is the authority of Blackstone that it stuck,” Carpenter said. “So both in popular culture and academic writing, Magna Carta becomes essentially the charter of King John in 1215.”

However, in a twist of irony, the actual law still acknowledges the truth. “There are still chapters of Magna Carta on the Statute Book of the United Kingdom today,” Carpenter said. “And actually, on the Statute Book, it's still the 1225 charter of Henry III.”

Recognising the importance of the 1225 Magna Carta doesn’t mean disregarding 1215 entirely; the original document set events in motion. But without the 1225 version, Magna Carta likely wouldn't have survived. “Without the 1225 charter, and without putting it on a consensual basis – so it's a freely entered into bargain between king and kingdom, supported by the church – I think without that too, the charter would not have survived," says Carpenter.

Carpenter's view is that we ought to see the 1215 and 1225 charters together in tandem, but he also argues that 11 February 2025 is a good moment to reflect on the fact that the Magna Carta we think we know isn't quite the full story.

Professor David Carpenter was speaking to David Musgrove on the HistoryExtra podcast. Listen to the full conversation