Decretum Gratiani
Black's Law Dictionary · Henry Campbell Black, M.A. · 1910
Black's Law Dictionary
Gratian's decree or decretum. A collection of ecclesiastical law in three books or parts, made in the year 1151, by Gratian, a Benedictine monk of Bologna, being the oldest as well as the first in order of the collections which together form the body of the Roman canon law.
1 Bl. Comm. 82; 1 Reeve, Eng. Law, 67.