Conversation so far:
In what area did Lewis do Bernard Lewis's research?
He is a pioneer of the social and economic history of the Middle East and is famous for his extensive research of the Ottoman archives.
Was it unusual to get access to the Ottoman archives?
He began his research career with the study of medieval Arab, especially Syrian, history.

Question: Did he follow up with more research?
Self-contained rewrite: After researching medieval Arab, did Bernard Lewis follow up with more research?