Within these walls - Jo Lyon

Roman and later activity was recorded north of Newgate, with
the Roman defensive wall and a medieval bastion preserved in the
new development. Stream channels gave way to early Roman
settlement, with the city's defensive wall built in the late 2nd
century AD. The defensive ditch was redug in the Late Saxon
period and the Roman wall repaired, with the area becoming the
site of the Greyfriars Friary in 1225. The City's growth saw the
ditch built over by the mid 16th century and the friary was
suppressed at the Dissolution. By the mid 18th century most of
the city wall had been demolished and the Giltspur Street Compter
prison was constructed in 1787-91. Later buildings included St
Bartholomew's Hospital and the General Post Office.