- Corsino, Pietro di1
- Cortigiani, Giovanni1
- Cosimo I, Grand-Duke of Tuscany, 1519-15744
- Cosimo II, Grand Duke of Tuscany, 1590-16211
- Cosimo III, Grand-Duke of Tuscany, 1642-17231
- Cosmetics--Moral and ethical aspects1
- Cosmography8
- Cosmology4
- Cosmology, Ancient1
- Cost1
- Costapellegrina, Giovan Andrea1
- Coton, Pierre, 1564-16261
- Cottricciaio, Mariotto1
- Council of Basel2
- Council of Ephesus1
- Council of Pisa--(2nd : 1511-1512)1
- Council of Trent2
- Council of Vienne1
- Councils and synods, Ecumenical1
- Count Brunorius de Gambara1