Princess Anne opens US event to mark 800 years of Magna Carta One of only four copies of the Magna Carta to have been produced in 1215 went on display at the US Library of Congress on Thursday, in an exhibition opened by Britain's Princess Anne. The key foundational document of both the British and American legal systems was previously deposited here 75 years ago for safekeeping at the outbreak of World War Two, and now returns as events are planned around the world to mark the upcoming 800th anniversary of its signing. Amongst other things, the Magna Carta guaranteed the principle that no one was above the law. IMAGES AND SOUNDBITES.