- Cortigiani, Giovanni1
- Corvus3
- Cosimo I, Grand-Duke of Tuscany, 1519-15746
- Cosimo II, Grand Duke of Tuscany, 1590-16211
- Cosimo III, Grand-Duke of Tuscany, 1642-17231
- Cosmetics--Moral and ethical aspects1
- Cosmochronology1
- Cosmography12
- Cosmology8
- Costapellegrina, Giovan Andrea1
- Coton, Pierre, 1564-16261
- Cottricciaio, Mariotto1
- Council of Basel2
- Council of Pisa--(2nd : 1511-1512)1
- Council of Trent3
- Council of Vienne1
- Counter-Reformation3
- Country life1
- Court administration1
- Court decisions and opinions1