Perhaps you should try some spelling variations:
"lettres patentses" » "lettres patents", "letters patents", "lettres galantes", "lettres patentsses", "letters patentses", "lettres pateses"
"lettres patentes" » "lettres patentses", "letters patentes", "lettres patees"
"lettres patent" » "lettres patents", "letters patent", "lettres pate"

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: (((("lettres patentes") OR ("lettres patentses"))) OR ("lettres patent")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"lettres patentes\") OR (\"lettres patentses\"))) or (\"lettres patent\"))".
• Removing quotes may allow a broader search: (((( lettres patentes ) OR ( lettres patentses ))) or ( lettres patent )).
• Adding a wildcard symbol may retrieve word variants: (((("lettres patentes") OR ("lettres patentses"))) or ("lettres patent"))*.