Ely Cathedral - Octagon
Ely Cathedral began as a monastery in AD 673 founded by St Etheldreda. The Danes destroyed it and Abbot Simeon rebuilt it in 1081. The central tower fell in 1322.
Alan of Walsingham rebuilt it in the design of the Octagon. No trace now remains of the Anglo-Saxon monastery founded in 673 and refounded in 970. After the Norman Conquest in 1066, and the putting down of the local rebellion of Hereward the Wake immediately after, the first Norman Abbot began to rebuild the Abbey on a new and larger scale.
More info: www.elycathedral.org/