The Roman wall was further developed in the medieval period with the addition of crenellations, more gates and further bastions. This shows a 13th century Bastion within the Barbican estate.

Another 13th century Bastion seen from the upper floor of the Museum of London. The section of wall near the Museum of London was revealed at Noble Street, after the devastation of an air raid on 29 December 1940 at the height of the Blitz.