Little or nothing was known of the S side of insula 22 until 1931. Note in Wire's diary 19-6-1851: "visited the sewerage works in the street leading to the castle (Museum Street) by Mr Crosse's broker. The foundation of the outer wall of the castle was discovered about 18" below the surface and though built of the same materials as that structure it was a very difficult matter to break it up". <1> Fragment of wall, possibly Roman, running E-W found in 1917 under Museum Street. <2>