Liber diurnus Romanorum pontificum (Latin for "Journal of the Roman Pontiffs") is the name given to a miscellaneous collection of ecclesiastical formulae used in the Papal chancery until about the 11th century.
[1] The collection contains models of the important official documents usually prepared by the papal chancery; particularly of letters and official documents in connexion with the death, the election, and the consecration of the pope; the installation of newly elected bishops, especially of the suburbicarian bishops; also models for the profession of faith, the conferring of the pallium on archbishops, for the granting of privileges and dispensations, the founding of monasteries, the confirmation of acts by which the Church acquired property, the establishment of private chapels, and in general for all the many decrees called for by the extensive papal administration.
The collection opens with the superscriptions and closing formulae used in writing to the Emperor and Empress at Constantinople, the Patricius, the Exarch and the Bishop of Ravenna, to a king, a consul, to patriarchs, metropolitans, priests and other clerics.
All "seem to be free reelaborations, mainly for monastic use, of official texts from the papal curia and the perhaps most famous and authoritative episcopal ones, for study in the schools of the monasteries and repeatedly updated for this purpose" (Vatican Archives).
[3] Scholars agree that papal letters written after the late eleventh century do not draw on the Liber diurnus.
In the late eleventh century, Cardinal Deusdedit copied several formulae from an unknown version of the Liber diurnus into his canon law collection.
Pressure from the ecclesiastical censors led to the edition printed at Rome in 1650 being withheld from publication, the copies being stored at the Vatican.
After Garnier's edition appeared in 1680, Benedict XIII in 1725 permitted the issue of some copies of Holstenius' text, but only in incomplete form and with a title page containing the wrong publication date "1658".
In his Museum Italicum (I, II, 32ff) Jean Mabillon and Michel Germain, who had seen Codex V during their stay in Rome in 1685, corrected many of Garnier's errors and printed some formulae anew.
It is sometimes claimed[2] that another edition based on Codex A was published in Milan in 1891 by Achille Ratti, a younger collaborator of Ceriani, and later to become Pope Pius XI.
Theodor von Sickel, in the "Prolegomena" to his 1889 publication of the text of the Vatican manuscript (the only one then known to exist) showed that the work possesses by no means a uniform character.
investigated more closely the case of some of the formularies attributed by Sickel to one of the aforesaid periods, and attempted to indicate more nearly the occasions and pontificates to which they belonged.
That hypothesis has now been abandoned, especially since it has been shown that this manuscript reached the library of Santa Croce in Gerusalemme from that of the Benedictine monastery of Nonantola.
Liber diurnus Romanorum Pontificum ex antiquissimo codice ms. nunc primum in lucem editus, ed.
Liber diurnus, ou Recueil des formules usitées par la Chancellerie Pontificale du Ve au XIe siècle, ed.