Just a shame the actual thing was a monumental failure, rejected by John, annulled by the Pope and not even followed by the Barons who wrote it (they were supposed to surrender London but refused to do so).
It's only after the French King Louis withdraws from the Baron's Rebellion (they had invited him to become king of England) after the decisive defeat of the French fleet by a navy under Hubert de Burgh in the Battle of Sandwich (1217) that a lasting document would be written, largely resembling both the Magna Carta and the a more pro-King (by this time the minor King Henry III) charter of 1216.
King Henry's minority government were by no means bound by the Magna Carta either, although as it recovered from the rebellion it made careful steps to stick to the 1217 agreement. Indeed, it's not until 1223 that the young King acknowledges that he considers himself bound by them and it's not until 1225 that the Carta is reissued - a price for the £40,000 of taxes the King asked to raise to finance the defence of Gascony after Louis attacked that province.
The Magna Carta also didn't establish any kind of system where the government was required to obey the same laws as everyone else. Indeed, whilst establishing that the barons had certain rights and those were to be respected, it does not mention any kind of establishment of rights for the lower classes. It limits government only in those areas where the government would infringe on the barons, and even then, the barons were still subject to the Royal Courts.
In the century following the Magna Carta declarations it was only periodically reissued and indeed remained a thing of dispute. The 2nd Barons Revolt happened in 1264 (after French arbitration found in favour of King Henry instead of a group of Barons who staged a coup in 1258 on the basis that the King was not following the Magna Carta) and was put down by Henry III's son, the future Edward I, who also invoked Magna Carta in his attempts to win support for the monarchy, by declaring that the Barons had gone further than Magna Carta allowed them to. Following the end of the Revolt, in 1267, Henry issued a declaration reaffirming commitment to Magna Carta.
Edward I, in 1297, affirms the 1225 Magna Carta in order levy taxes, and its this document that has legal standing today - although it has been largely repealed. The Papacy remained opposed to the Magna Carta however, and Pope Clement V issued a Papal Bull in 1305 annulling it - although it was reaffirmed by English and later British monarchs throughout the ages.
The 1215 document was a political attempt to force a further civil war. It's the 1225 and 1297 documents that should be celebrated, but I suppose its the event that is commemorated rather than the document itself.
