Papal letters, themselves having the force of law and specifically written to an individual or to a group in answer to a question on some point of canon law. The first such definitely established decretal was from Pope Siricus to Bishop Himerius of Tarragona (a.d. 385), though Damasus (d.384) might have issued one. From the start, popes insisted that decretals had the force of law. * compiled the earliest influential decretal collection. Various collections were made in the following centuries, but Gratian's Decretum (c.1140) set a new standard in the grouping of the decretals according to the different points of law they dealt with. Though his collection (which included some forgeries) ranged over many centuries, it concentrated on more recent pontificates and this became the accepted trend of subsequent decretal collections. The definitive medieval collections were the Decretals of (1234), 's Liber Sextus (1298), and Clement V's Constitutiones Clementiae. Later John XXII's Extravagantes (1325) and the Extravagantes Communes (c.1500) were added unofficially.