For any two documents you grouped togetherIs this the same thing? What would it mean if it were?
For any two documents you did not group togetherWhat would you have to believe for these to belong in the same group?
About your group namesWhat does the name you chose reveal about what you were sorting by?
About the people who wrote theseWhat did each writer think they were doing? What did they think was true about the world?
About professional languageSeveral of these documents are written in neutral, administrative, or professional registers. What does that register do?
About timeSome of these documents span five centuries. Does that matter? What changes? What doesn't?