Former Owner
- Carleton Rubira Richmond1
- Carlo Archinto, 2nd Marquess of Parona, 3rd Count of Trainate1
- Carlo Bonaparte1
- Catharine Wisser1
- Caxton Club1
- Cecil Deedes1
- Chapelle du monastère du Carmel de Nantes1
- Charles Bruce, 3rd Earl of Ailesbury1
- Charles Butler1
- Charles D. Humberd1
- Charles Hope, 3rd Marquess of Linlithgow1
- Charles Hurleston1
- Charles Marriette1
- Charles Stephen Ascherson1
- Christian Gottlieb Schwarz1
- Christopher Pease, 2nd Baron Wardington1
- Chrétien-François II de Lamoignon1
- Claude Joseph Constant Despine1
- Collegium Germanicum et Hungaricum1
- Coluccio Salutati1