- Courtesy books1
- Courts and courtiers1
- Coutinho, Francisco de Sousa, 1597 or 1598-16601
- Creation1
- Creeds1
- Cryptography1
- Cueva y de Castilla, Beltrán III de la, Duke of Alburquerque, -16121
- Cueva, Andrea della1
- Cur Deus homo (Anselm, Saint, Archbishop of Canterbury)1
- Curiosities and wonders1
- Cynics (Greek philosophy)1
- Czech Republic--Brno1
- Daniel (Biblical figure)1
- Dante Alighieri, 1265-13211
- De bello Gallico (Caesar, Julius)1
- De ente et essentia (Thomas, Aquinas, Saint)1
- De finibus bonorum et malorum (Cicero, Marcus Tullius)1
- De gradibus humilitatis et superbiae (Bernard, of Clairvaux, Saint)1
- De institutione musica (Boethius)1
- De mundo (Aristotle)1