after the decline of the roman empire, few people remained in london. the anglo-saxon people of sub-roman britain were mainly agricultural. once the romans had gone, trade with continental europe dwindled. in the 9th century, more people started living in london again. it became the largest city in england. however, it did not become the capital city of england again until the 12th century. for a long time after the romans, england was not unified, and so had no capital.