Former Owner
- City College of New York1
- Clarence Howard Clark, Sr.1
- Clarence S. Bement3
- Claude Joseph Constant Despine1
- Claude Le Muet1
- Claude de Fonsèque1
- Clemente Carilli1
- Coella Lindsay Ricketts25
- Collegium Germanicum et Hungaricum1
- Cologne Charterhouse3
- Coluccio Salutati1
- Comte André de Riaucourt1
- Conradus Eerens1
- Convent San Marco1
- Coppo family1
- Cordwainer Smith1
- Cornelius John Hauck1
- Cortlandt F. Bishop1
- Cosimo de' Medici1
- Count Alexis de Golowkin1