Legend suggests the St. Gregory The good (d. 604) listened to the very first a few lines chanted by angels on a particular Easter morning in Rome though he walked barefoot in an awesome spiritual procession and that the saint thereupon included the fourth line: “Ora Professional nobis Deum. Alleluia.” https://vita-pro-nobis31086.look4blog.com/69865599/the-greatest-guide-to-vita-pro-nobis