Name
- Cesarei-Leoni, Francesco, Cardinal1
- Chinucci, Luigi1
- Circello, - di, Marchese1
- Codronchi, A-1
- Colloredo, Franz Gundaccar, Prince1
- Consalvi, Ercole, Cardinal, Papal Secretary of State1
- Coppola, Domenico, Archbishop of Mira1
- Corona, Niccola1
- Corsini, Neri Maria Giuseppe1
- Corsini, Tommaso, Prince of Sisismeno1
- Cortois de Pressigny, Gabriel, Bishop of St Malo1
- Cristaldi, Belisario, Cardinal, Papal Auditor and Treasurer1
- Dalberg, Karl Theodor Anton Maria, Baron, Archbishop of Mainz and Prince Primate, 1744-18171
- Damiano, Philippo, Sardinian envoy at Rome, fl 1773-17881
- Daru, Martial Noel Pierre, Baron, military administrator and Intendant of the Crown at Rome, 1774-18271
- Donato, Carlo, correspondent of Francesco Cancellieri, fl 17921
- Dugnani, Antonio, cardinal, papal nuncio and Archbishop of Rhodes, 1748-18181
- Duminique, -, Baron, secretary to the Elector Palatine of the Rhine, fl 17841
- Egerton, Francis Henry, 8th Earl of Bridgewater, 1756-18291
- Ercolani, Luigi, Italian cardinal, 1758-18251