Angelica Patrone, Beate Spiritus. [Guardian Angels.] This hymn, of unknown authorship and date, is in the Corolla Hymnorum, Cologne, 1806, p. 67. Daniel gives it without note or comment in ii. p. 376. It is also found in Simrock, p. 338; Bässler, No. 137, and others. [Rev. W. A. Shoults, B.D.]
Translation in common use:—
Sweet Angel of mercy. By E. Caswall. It appeared in his Masque of Mary and Other Poems, 1858, in 8 stanzas of 8 lines, and in his Hymns and Poems, 1873, p. 180. It is given in a few Roman Catholic collections for Schools and Missions.
-- John Julian, Dictionary of Hymnology (1907)