Oratorio, a musical composition on a sacred theme, dramatic in form and associated with orchestral accompaniments, but without scenic accessories; it derives its name from the oratory of St. Philip Neri at Rome, in which a composition of the kind was first performed, and was a musical development of the miracle plays (q.v.).
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Orangemen * Oratory, Congregation of the