The collection consists of 97 letters and documents, chiefly in Italian but also including some in Latin, dating from 1598 to 1699. Included is correspondence of various Church and political figures of the 17th century, primarily in Florence, Pisa, and Rome, as well as some in Bologna, Correggio, Parma, and Siena. Many letters contain information pertaining to military and diplomatic history, focusing on the Farnese dukes of Parma, the Spanish occupation of Milan, and the political ambitions of the Holy See.

Letters within the collection provide sources and background for a number of influential individuals from the period: Diego d'Avalos, Marchese of Vasto [Perugia]; Francesco Boncompagni, grandson to Pope Gregory XIII, whom he mentions in his letter to Angelo Cesi (1530-1606); Tommaso Caccini, Dominican friar who was instigating the castigation of Galileo at the time of his letter sent to his brother Matteo (April 1612); Baldassare Cenci, Archbishop of Fermo, who wrote a letter to Cardinal [Fabrizio] Spada, papal secretary of the state, about the scandalous divine cults in the ecclesiastical domains; correspondence with Francesco Gaetani or Caetani (possibly Francesco Caetani, duke of Sermoneta, 1594-1683), dating from 1610 to 1639; and Quintillio Petrucci, probably a papal correspondent in Parma, who wrote 2 letters to Antonio Roffi in Florence containing news about members of the Visconti and Gonzaga families, among others. Also includes 2 documents from the Monache di San Giuseppe di Pisa for Lucretia della Seta and Suor Costanza Medici (1645 and 1647). Also included are one unidentified letter in German and one pen-and-ink drawing of a proposed coin or medal (43 mm. in diameter), with a motto on the obverse reading "Syrus Austriacus Corrigi Com[es]"), designed for D. Giovanni Siro of Correggio (1590-1645).