It was probably begun in 1246 and completed around 1255 as part of Henry III’s re-building of the Abbey and is one of the largest of its kind (internally 18 metres or 60 feet). It is octagonal in shape with tiered seating for up to eighty monks and an imposing central pillar, fanning out to a vaulted ceiling. Henry of Reyns was the supervising master mason, probably with Master Aubrey.

+info: Westminster Abbey.