Perhaps you should try some spelling variations:
upon conversations » union conversations, open conversations, spoken conversations
christianity upon » christianity among, christianity along, christianity from
reef history » brief history, reeves history, reef fishery
17th century » 19th century, 20th century

Try widening your search to All Fields.

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: %christianity upon conversations %a german %reef history %2023 ((18th century) OR (17th century))%22.
• Adding a wildcard symbol may retrieve word variants: %christianity upon conversations %a german %reef history %2023 ((18th century) or (17th century))%22*.