When the Saxon King Edward the Confessor died in 1066, he left no heirs, kicking off a three way battle for the English crown. You can read about it here.
William, Duke of Normandy, won the fight for the crown and marched on from the Battle of Hastings to London. He was crowned king at Westminster Abbey on 25 December 1066.
William built three military camps on London, to keep control of the city. One eventually became known as the Tower of London. William and his successor built the White Tower.
The Tower is one of the most important buildings to have survived from Norman times
A ring of monastries, nunneries, priories and hospitals grew up on the outside of the old Roman city, and in 1176 the first stone bridge was built across the Thames.
After a fire in 1087, a new cathedral, St Pauls, was built.
William II started on the great hall at the Palace of Westminster.
Around 1190, london had its first mayor, Henry Fitz Aylwin.
The first Guidhall was built in 1127, on the ruins of the Roman amphitheatre. The Guidhall seen today, on the same site, dates from 1411.
Lead pipes were used to bring spring water into the city from 5 km away - one of the first water systems in medieval Europe.
New inhabitants from Europe set up businesses in London. These included many Jews who set up business in the Cheapside area, and Flemish and French cloth workers who helped make London a centre for the Europeam wool trade.
The weavers guild was set up in 1130. Within 50 years there were 20 guilds, including goldsmiths, pepperers (the spice trade), cloth workers and butchers.
By the 13th century London had a population of 80,000, making it one of the largest cities in Europe.
London was home to Englands first parliament, as well as the law courts and the Exchequer that organised the royal finances.
The Church was London's biggest landowner and its biggest employer.
London experience one disaster after another with the most deadly being the Black Death, brought over by rats on ships from Europe. This bubonic plague wiped out half of all Londerners in just 18 months, and it took 150 years for the population to recover.