In 1321, under the sacrist Alan of Walsingham, work began on a large free-standing Lady Chapel, linked to the north aisle of the chancel by a covered walkway. The chapel is long and wide, and was built in an exuberant 'Decorated' Gothic style over the course of the next 30 years. Masons and finances were unexpectedly required for the main church from 1322, which must have slowed the progress of the chapel. The north and south wall each have five bays, comprising large traceried windows separated by pillars each of which has eight substantial niches and canopies which once held statues.