Perhaps you should try some spelling variations:
"william robert pitt" » "william robertson pitt", "william robert pigott", "william robert pate", "william robert post"
"william robert pigot" » "william robertson pigot", "william robert pigott", "william robert piggott", "william robert pool"
"william ridgeway pitt" » "william ridgway pitt"

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (((("william robert pitt") OR ("william robert pigot"))) OR ("william ridgeway pitt")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"william robert pitt\") OR (\"william robert pigot\"))) or (\"william ridgeway pitt\"))".
• Removing quotes may allow a broader search: (((( william robert pitt ) OR ( william robert pigot ))) or ( william ridgeway pitt )).
• Adding a wildcard symbol may retrieve word variants: (((("william robert pitt") OR ("william robert pigot"))) or ("william ridgeway pitt"))*.