Magna Carta was an agreement between King John and a group of English barons in response to years of the king’s misrule and excessive taxation. Despite a closing line suggesting the charter was “Given by [John’s] hand,” the charter was more or less forced on him by the barons. Many 19th-century historians suggested that the charter was written by one of its most influential signers, Archbishop of Canterbury Stephen Langton. However, the document’s exact wording was likely the product of months of back-and-forth negotiations between the king and his noblemen.

The roots of Magna Carta are found in other charters granted by English kings at the beginning of their reigns. In 1100, Henry I had issued a 20-clause coronation charter, promising to rule justly, offer the church greater financial freedom and reduce royal meddling in the marriages and family inheritances of his barons.

Although Henry kept few of these promises, his charter nonetheless served as a basis for the barons’ negotiations in 1215. Magna Carta was unique, however, in several respects, including its length and detail, its timing (it had been 60 years since the last royal charter) and the fact that it was less an offering by the king to his nobles than a demand by the nobles to their king.

Intended as a peace treaty, this first Magna Carta never took full effect and failed to avert war between John and the nobles. By September of 1215 the barons had garrisoned Rochester Castle in opposition to the king, while John had successfully petitioned the Vatican to have Magna Carta annulled and all the rebels excommunicated. It was only in 1225 that a new king, 9-year-old Henry III, reissued an abridged version of Magna Carta as his own coronation charter.

Magna Carta laid a foundation for lasting legal concepts like the ban on cruel and unusual punishments, trial by a jury of one’s peers and the idea that justice should not be sold or unnecessarily delayed. But the document also addressed very specific concerns that don’t quite echo through the ages, including a ban on fishing weirs and a mandate on the proper width for the bolts of cloth used to make monk’s robes.

When Henry III reissued Magna Carta its 69 clauses had been reduced to 27. It remained that way, with minor changes, until the 19th century, when British parliamentarians set about pruning obsolete laws from the many-layered British legal code. By the mid-20th century, only three clauses remained on the books. These remaining laws grant freedom to the Church of England, guarantee the customs and liberties of the city of London and—most importantly—forbid arbitrary arrest and the sale of justice.

Multiple copies of the first Magna Carta (a sheet of parchment with approximately 3,600 words written in vegetable-based ink) were distributed to individual English county courts during the summer of 1215. Today four of those copies survive; the British Library holds two, and the other two are in the collections of the cathedrals at Salisbury and Lincoln.

At the beginning of World War II, Winston Churchill tried to force Lincoln Cathedral to donate its original Magna Carta to the United States, where it had been on display, in hopes that such a gift would create support for an alliance with Great Britain. Such a strong-armed donation would, of course, have run contrary to the property rights enshrined in the document itself. In the end, the cathedral’s Magna Carta spent the war under guard at Fort Knox, but was returned to England after the war.

A handful of other Magna Cartas are versions issued between 1225 and 1297, when the charter officially entered the English statute books. In 2007, a 1297 Magna Carta sold at auction for $21.3 million, the most ever paid for a single page of text.

According to standard British usage, King John’s Great Charter has 63 clauses but no definite article—it’s simply referred to as Magna Carta, without the “the.” The charter was written in Latin (in which there are no exact equivalents for “an” or “the”), and signed by men who would have been fluent in Latin, French and Middle English. But for American newspapers, museum exhibitions and politicians, Magna Carta nearly always merits the article.