 The dialogue is presented between a letter to Pope Urban III and another letter, a literary structure that has been traced back to Sulpicius Severus.The identification of the author of the "Dialogus" and the canonist author of "Summula decretionum quaestionum", dated c.1180, was made by N. M. Häring; but this is not universally accepted.The "Summula" is a digest of the "Summa" of Sicardus of Cremona.