 To this collection he gave force of law by the Bull "Rex pacificus", 5 September 1234.This collection is also known to canonists as the "Liber extra", i. e. extra Decretum Gratiani.Boniface VIII published a similar code on 3 March 1298, called the "Sixth Book of the Decretals" (Liber Sextus), including the "Regulæ Juris".