[Footnote 76: Petavius (Dogmat. Theolog. tom. v. l. v. c. 2,
3, 4, p. 217 - 225) and Tillemont (Mem. Eccles. tom. xiv. p.
713, &c., 799) represent the history and doctrine of the
Trisagion. In the twelve centuries between Isaiah and St.
Proculs's boy, who was taken up into heaven before the
bishop and people of Constantinople, the song was
considerably improved. The boy heard the angels sing, "Holy
God! Holy strong! Holy immortal!"]