 After the fire of 1270 , a programme of reconstruction was launched , with repairs and a major enlargement . Outer aisles were added to the nave , the eastern wing comprising the choir and presbytery was doubled in length and had aisles provided on its north and south sides , and the octagonal chapterhouse was built off the new north choir aisle ( <unk> . 8 & 9 ) . The new northern and southern aisles ran the length of the choir , past the first bay of the presbytery , and contained <unk> and chest tombs . The south aisle of the choir contained the tomb of bishop John of Winchester , suggesting a completion date for the reconstructed aisle between 1435 and <unk> ( Fig . 10 ) . Chapels were added to the new outer aisles of the nave and were partitioned from each other with wooden screens . The first bay at the west end of each of these aisles and adjacent to the western towers did not contain a chapel but instead had an access door for the laity . 
