When William the Conqueror arrived in 1066 he made London his HQ and following his Norman strategy built up a nation-wide system of defensive castles. The most famous one in London being the Tower of London built at the place were the old Roman city wall joined the Thames at it's eastern limits. The original Castle, now almost 1000 years old, was called the White Tower and can still be visited within the walls of the Tower of London. The Tower of London remained a home for the kings from 1087(William 2nd ) to 1500 (Henry 7th ).

During this period and until the end of the middle ages, that is for the next 500 years London remained much the same as follows.
·The main city area remained within the original Roman city walls.
·A new area to the west at Westminster was established as the headquarters for the King and all the trappings for running the country plus the magnificent Westminster Abbey. Government offices like the Treasury were slowly moved from Saxon Winchester to Westminster. The City of London and The City of Westminster were connected by both road and river. The latter was the fastest route and other than for processions the river was always used by the Kings. The road route can still be followed today. West to East: Whitehall, Trafalgar Square, turn right The Strand, Fleet Street then through Ludgate (now circus.)
·The area of Southwark is in exactly the same place now as in Roman times.
·London Bridge was the only connection between the walled City and Southwark and the important roads south, notably to Winchester and Dover for France.

Two building projects early in this period are worth noting.
·Lambeth Palace was built as the London home for the Archbishop of Canterbury. Lambeth then as now is almost directly across the river from Westminster Abbey. 1000 years ago both areas were surrounded by marshes so the best route from one to the other would be to take the short ferry boat trip across the river.
·London Bridge was rebuilt in stone in 1172. Up to this time the bridge was made of wood. This new bridge with 19 arches was completed 33 years later. The driving force behind the new bridge and indeed of many other bridges was the church who spread the message that bridges should be financed with free gifts from the public (alms). This stone bridge lasted 600 years. Gifts, rents and taxes collected by the church became significant and this same trust recently also funded Blackfriars and Tower Bridge and purchased Southwark bridge. Early income sources included; tolls on carts using the bridge, tolls from ships passing under the bridge and fines from illegal fishing from the bridge.

It is also worth noting the vast number of churches that were built in London at this time. (Over 100 by 1200 AD)

Population. Maximum 80,000 people between 500 and 1000 years ago falling to perhaps 40,000 during the times of the plague. The bulk of Londoners lived within the old (Roman) city walls.