I want to know the answer to the following question:
By the late 7th century, what was a main function of Lundenwic?
All the background I'm provided with is that "With the collapse of Roman rule in the early 5th century, London ceased to be a capital and the walled city of Londinium was effectively abandoned, although Roman civilisation continued in the St Martin-in-the-Fields area until around 450.". Is that enough to answer the question?