The expansion and rebuilding of Roman London led to a south bank settlement, which added acreage and and addition of a bridge. This new settlement helped to advance innovations, and London was growing in population and in ideas. Londinium was at its peak around this time, and had an estimated population of about 25,000 citizens. The south bank settlement was set on two islands in the Thames River, and housed citizens, acting as a city of its own. 

Source:

Ross, Catherine and Clark, John. “Roman London.” London: the Illustrated History. Penguin, 2011. pp. 31–32.

Photograph by: 

“Londinium.” Wikiwand.com.