The oldest of the Sacramentaries or liturgical books.
Only one manuscript is known, dating from the 7th century.
Found in the library of the Cathedral Chapter of Verona, it was published by Joseph Bianchini in 1735 in the fourth volume of his edition of and was by him arbitrarily attributed to Pope Leo I (440-461).
On the strength of this attribution the book was included by the Ballerini in their edition of Leo (Venice, 1753-1757), and still bears the name Leonine.
It contains neither Canon nor Ordinary of the Mass, but a collection of Propers (Collects, Secrets, Prefaces, Postcommunions, and Orationes super Populum), of various Masses, together with ordination forms arranged according to the civil year and with much disorder.
New Catholic Dictionary