Pierre Mandonnet, OP (1948) St. Dominic and His WorkArchived 18 June 2012 at the Wayback Machine, Translated by Sister Mary Benedicta Larkin, OP, B. Herder Book Co., St. Louis/London, Chapter III, note 50: "If the installation at Santa Sabina does not date from 1220, at least it is from 1221. The official grant was made only in June 1222 (Bullarium OP, I, 15). But the terms of the bull show that there had been a concession earlier. Before that concession, the Pope said that the friars had no hospitium in Rome. At that time St. Sixtus was no longer theirs; Conrad of Metz could not have alluded to St. Sixtus, therefore, when he said in 1221: "The Pope has conferred on them a house in Rome" (Laurent no. 136). It is possible that the Pope was waiting for the completion of the building that he was having done at Santa Sabina, before giving the title to the property, on 5 June 1222, to the new Master of the Order, elected not many days before." Accessed 20 May 2012.
O'Connor, John Bonaventure (1913). "St. Dominic". In Herbermann, Charles (ed.). Catholic Encyclopedia. New York: Robert Appleton Company. Retrieved 31 October 2020.
Pierre Mandonnet, OP (1948) St. Dominic and His WorkArchived 18 June 2012 at the Wayback Machine, Translated by Sister Mary Benedicta Larkin, OP, B. Herder Book Co., St. Louis/London, Chapter III, note 50: "If the installation at Santa Sabina does not date from 1220, at least it is from 1221. The official grant was made only in June 1222 (Bullarium OP, I, 15). But the terms of the bull show that there had been a concession earlier. Before that concession, the Pope said that the friars had no hospitium in Rome. At that time St. Sixtus was no longer theirs; Conrad of Metz could not have alluded to St. Sixtus, therefore, when he said in 1221: "The Pope has conferred on them a house in Rome" (Laurent no. 136). It is possible that the Pope was waiting for the completion of the building that he was having done at Santa Sabina, before giving the title to the property, on 5 June 1222, to the new Master of the Order, elected not many days before." Accessed 20 May 2012.
See Bernard Hamilton (1981) The Medieval Inquisition, pp. 36–37, New York: Holmes & Meier; Simon Tugwell [Wikidata] (1982) Early Dominicans: Selected Writings, p. 114, note 90, Ramsey, New Jersey: Paulist Press