Norwich Cathedral in Norfolk is one of the finest examples of Norman cathedral architecture in England. The Normans wanted to have cathedrals in the largest towns; and in the late eleventh century Norwich, with its castle and market, was one of the most important towns in England. The cathedral was founded by Bishop Herbert de Losinga, and building commenced in 1096. It was not consecrated until 1278, but was finished considerably before that date.
The vaulting is covered with sculptured stone bosses, which tell Biblical stories from the Creation to the Apocalypse.
The roof bosses of Norwich Cathedral are one of the great glories of medieval art. Over a thousand of these carved and brightly painted keystones were placed high in the stone vaulting between 1315 and 1500. Difficult for human eyes to see for 500 years, 'visible only to the angels', the carvings tell stories from the Old and New Testaments, and vividly bring to life many important beliefs and stories of the Middle Ages. 
A roof boss is a keystone which holds in place the ribs of the vaulting. The bosses in Norwich Cathedral are between eight and twenty-four inches wide. Quite a few Norman churches had bosses, but by the end of the thirteenth century (the Gothic period) they had become more elaborate. At first, they were simple leaves or flowers. Soon they were being used to tell stories. Sometimes a single boss tells a story, but often a row of bosses tells a longer narrative. The last story-telling bosses in Norwich Cathedral were carved after a fire in 1509.
