- Christian life--Catholic authors1
- Christian literature, Early1
- Christology1
- Church finance1
- Church history1
- Contemplation1
- Cosimo I, Grand-Duke of Tuscany, 1519-15741
- Courts1
- Courts and courtiers1
- Criminals1
- Criticism, interpretation, etc.1
- Crucifixion of Jesus Christ1
- Cults1
- Devotional literature, Italian1
- Devotional literature, Latin (Medieval and modern)1
- Diaries1
- Diplomatic documents1
- Diplomats1
- Dominicans1
- Eleonora, di Toledo, Duchess, consort of Cosimo I, Grand-Duke of Tuscany, 1522-15621