The common law, as it then prevailed in England, was in a great measure composed of some remnants of the old Saxon customs, joined to the feudal institutions brought in at the Norman Conquest. And it is here to be observed, that the constitutions of Magna Charta are by no means a renewal of the laws of St. Edward, or the ancient Saxon laws, as our historians and lawwriters generally, though very groundlessly, assert. They bear no resemblance, in any particular, to the laws of St. Edward, or to any other collection of these ancient institutions. Indeed, how should they? The object of Magna Charta is the correction of the feudal policy, which was first introduced, at least in any regular form, at the Conquest, and did not subsist before it. It may be further observed, that in the preamble to the great charter it is stipulated that the barons shall hold the liberties there granted to them and their heirs, from the king and his heirs; which shows that the doctrine of an unalienable tenure was always uppermost in their minds. Their idea even of liberty was not (if I may use the expression) perfectly free; and they did not claim to possess their privileges upon any natural principle or independent bottom, but just as they held their lands from the king. […]
All these were marks of a real and grievous servitude. The great charter was made not to destroy the root, but to cut short the overgrown branches of the feudal service[.]
Edmund Burke An Essay towards an Abridgement of English History, written between 1757 and c. 1763. From Edmund Burke (1852) The Works and Correspondence of the Right Honourable Edmund Burke, in Eight Volumes, Vol. IV, London: F. & J. Rivington, pp. 358-9 (Google Books)
Through the 17th and into the 18th century, it had been argued that England’s constitution was ancient: a single constitution dating back to the Anglo-Saxons (or in some versions, the Britons). Here Burke argues against this in the instance of Magna Carta. He suggests that the charter was aimed at relieving burdens of the feudal system, such as excessive fines on heirs to an estate and forced marriage for male heirs and widows. The justice system was overhauled, removing its arbitrary and erratic nature. Another important aspect of the Magna Carta, to Burke’s mind, was that the freedoms the barons secured to themselves they were bound to allow to their subordinates, preventing England “degenerating into the worst imaginable government, a feudal aristocracy” (p. 360).
The Magna Carta applied to Ireland: the Magna Carta Hiberniae appears to have been issued in 1216. For more on the influence of Magna Carta in Ireland see the podcasts from the “Law and the Idea of Liberty in Ireland: From Magna Carta to the Present” conference held November 2016 listed here (also on Soundcloud and iTunes).
Sean McGlynn (2015) “The Road to Runnymede” in History Today Volume 65 Issue 7 (online).
British Library (2014) “English translation of Magna Carta”