- Cosimo I, Grand-Duke of Tuscany, 1519-15744
- Cosimo II, Grand Duke of Tuscany, 1590-16211
- Cosimo III, Grand-Duke of Tuscany, 1642-17231
- Cosmography1
- Cosmology1
- Costapellegrina, Giovan Andrea1
- Council of Pisa--(2nd : 1511-1512)1
- Courts and courtiers1
- Covoni, Luigi de1
- Creeds1
- Criminal law3
- Cristofano, Filippo di1
- Criticism and interpretation2
- Criticism, Textual1
- Criticism, interpretation, etc.1
- Crusades (Fifth) (1218-1221)1
- Cueva y de Castilla, Beltrán III de la, Duke of Alburquerque, -16121
- Cults1
- Customs administration2
- Cyprian War (1570-1571)1