The hymn beginning with Glory be to God on high,
etc. (Luke ii. 14); so called because the former part of it was sung by
the angel host that appeared to the shepherds of Bethlehem.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
More on Angelic Hymn from Fact Monster:
- Gloria in excelsis - Gloria in excelsis Gloria in excelsis [Lat.,=glory in the highest], the Angelic Hymn or greater ...