How many people lived in London by year 400?

The city of London was founded by the Romans in the 1st century AD, so there would have been people living in London by the year 400 AD. However, there are no reliable estimates of the population of London at that time. Some historians estimate that the population of London may have been as low as a few thousand people, while others believe that it may have been as high as 50,000 people.