Hereford Cathedral was founded in the year 696 and is dedicated to Ethelbert, a young late 8th-century king of East Anglia who was murdered on the orders of King Offa of Mercia (or his queen) and who was interred in the church. There is no trace of the earlier buildings; the current structures date from the 11th and 12th centuries and there is a magnificent Norman nave, with massive Romanesque arches. The Cathedral is famous for its chained library and its many treasures, not least the Mappa Mundi, a graphical representation of the medieval world, physical and spiritual, made (possibly for the Cathedral) by Richard of Holdingham in the early 14th century. The Chained Library, an early form of security system whereby books are literally chained to shelves in such a way that they can still be read, dates from 1611. Among its many manuscripts is an 8th century gospel and a copy of Magna Carta from 1217.