[4][a] Udo Heyn claims this was a Germanic notion,[4][b] and Phillip Wynn reports that it had long been believed in pagan antiquity by the time of this letter.
[5] Kelly DeVries regards the theology of Gravi de pugna as shallow and considers it to raise problems of theodicy and legitimacy as soon as the first Christian army loses.
[7] It was invoked to justify numerous wars, including by Hincmar of Reims, Rabanus Maurus, Sedulius Scottus, Ivo of Chartres, and Bernard of Clairvaux[8] It was also recited at the Siege of Lisbon in 1147 CE.
[6] Gravi imbued the Crusaders with confidence that God was on their side, squelching all moral concerns and leading to behavior that did not comply with then-accepted rules of war.
[9] The work lost influence with the renaissance of the 12th century, which developed more sophisticated jurisprudence and moral reasoning,[10] At the same time, Augustine's own opinions on just wars, which had been largely unknown, were studied by the decretists and through them, Aquinas as well.