Mancini was one of the oldest families of Roman nobility. Their titles and fiefs were numerous: Duke of Nevers and Donzy, Prince of Vergagne and of the Holy Roman Empire with the treatment of Serene Highness, French Peer, Spanish Grandee, Marquis of Fusignano, Count of Montefortino, Viscount of Clamecy, Baron of Tardello, Tumminii and Ogliastro, Lord of Claye-Souilly, Roman noble and Venetian patrician. They were knights of the Order of the Golden Fleece, of the Order of the Holy Spirit, of the Order of Saint Michael, of the Sovereign Order of Saint John of Jerusalem and many more. The humanist Marco Antonio Altieri (1457–1537) includes them in Li Nuptiali, an important collection of news about Rome in the 16th century. The family was granted the Honneurs de la Cour of France.