A large two - storey cloister with over 1,000 ceiling bosses was begun in 1297 and finally finished in 1430 after the Black Death had plagued the city .
A large two - storey cloister is the only such in England .
A large two - storey cloister , the only such in England , with over 1,000 ceiling bosses was begun in 1297 and finally finished in 1430 after the Black Death had plagued the city .