Former Owner
- Coppo family1
- Cordwainer Smith1
- Cornelius John Hauck1
- Corp. Thomas Tay1
- Cortlandt F. Bishop4
- Cosimo de' Medici1
- Count Alexis de Golowkin1
- Count Johann Nepomuk Wilczek1
- Couvent des Minimes (Clermont-Tonnerre, France)1
- Couvent des pères Franciscains (Monte-Carlo, Monaco)1
- Cover of a binding, illegible on what was the outer side.1
- Cox Macro1
- Craven Ord1
- Cristoferus Chrewczer1
- Curt H. Reisinger1
- Cyrus Adler1
- Cyrus Longworth Lundell1
- César de Missy1
- D'Assonleville family1
- D. Andreas Parisino1