Fortifications of London

The fortifications of London are extensive and mostly well maintained, though many of the City of London's fortifications and defences were dismantled in the 17th and 18th century. Many of those that remain are tourist attractions, most notably the Tower of London.

London's first defensive wall was built by the Romans around 200 AD. This was around 80 years after the construction of the city's fort, whose north and west walls were thickened and doubled in height to form part of the new city wall, and 150 years after the city was founded as Londinium.

The London Wall remained in active use as a fortification for over 1,000 years afterwards, defending London against raiding Saxons in 457 and surviving into Medieval times. There were six main entrances through the wall into the City, five built by the Romans at different times in their occupation of London.

These were, going clockwise from Ludgate in the west to Aldgate in the east: Ludgate, Newgate, Aldersgate, Cripplegate, Bishopsgate and Aldgate. A seventh, Moorgate, was added in Medieval times between Cripplegate and Bishopsgate.

After the Norman conquest in 1066 the city fortifications were added to, as much to protect the Normans from the people of the City of London as to protect London from outside invaders. King William had two fortifications built:

Later in the medieval period the walls were redeveloped with the addition of crenellations, more gates and further bastions.

The 'gates' that once guarded the entrances to the City of London through the City Wall were multi-storey buildings that had one or two archways through the middle for traffic, protected by gates and portcullises. They were often used as prisons, or used to display executed criminals to passers-by. Beheaded traitors often had their head stuck on a spike on London Bridge, then their body quartered and spread among the gates.

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