The walls were built relatively late for a Roman city, around the year 200.
How were the Roman walls of London built?
London did not offer the right stone for this construction and therefore had to come from the Maidstone area by navigating the Thames, where there was a a type of clay mixed with limestone that was strong enough for the walls.
Furthermore for the Romans it was a great architectural and logistical feat. One of the boats that was used to transport the material sank and was found in 1962 near Blackfriars Bridge. London’s Roman walls incorporated all gates and a fort, Moorgate being the only gate added in the Middle Ages. The walls were almost 3 km long and 5 and a half metres high, the width varied. On average it was around 2.5 meters. There was also a 2.5 meter moat around it.
In 400 AD the walls were reinforced and about 20 bastions were added, just before the Romans withdrew. For a long time the walls were abandoned, but they were still able to defend the city as for example against the Saxons in 457.
They were later repaired and maintained and only after 1500 did the city become too big for the walls. In the second half of the 1700s the Roman walls of London became a problem with increasing traffic and were slowly demolished along with the medieval gates.
The walls can still be seen in several places in London, mainly the City. You can still see pieces from the Barbican, near the Tower of London, Cooper’s Row, Noble Street and in the Museum of London garden.
The surprising thing when you think of the city walls and gates is how small London was then compared to London now. Areas that are very central to us now, were very far from the walls and considered countryside even a few centuries ago.
Close to the walls of London is the Barbican district. The name Barbican comes from the Latin Barbecana, here there was in fact a Roman fortress that was used for centuries until its destruction in 1500.