The Vallicelliana Library is located in the New Church's Square, on the second floor of the Oratory of the Philippines. The building, designed by architect Francesco Borromini in the seventeenth century, was built on commission of the Congregation of the Oratory of St. Philip Neri, in the years 1637 to 1667. The material preserved, whose original construction dates back to the works owned by Neri, and consists primarily of books on the history of the Church in the sixteenth century, during the Reformation and Counter-Reformation. The Library also manages the bibliographic heritage of the Roman Society of National History. The collection consists of approximately 130.000 volumes, including 3.000 manuscripts and several incunabula. There are also collections of engravings and old photographs.