Opus (Lat.)
Work; used by composers to indicate the order in which their works were written.
Oratorio (It.) [from Lat., oratorius, pertaining or belonging to prayer; a place for prayer]. A composition consisting of solos and concerted pieces for voices, the theme of which is taken from the Bible or from sacred history. The name arose from the fact that St. Philip Neri gave discourses intermingled with music in his oratory about the middle of the 16th century. The term Oratorio is also used for secular works written on the same plan, such as Haydn's "Seasons," and Bruch's "Odysseus," but is manifestly inappropriate. The oratorio is descended from those middle-age dramatic performances founded on biblical or moral themes, known as mysteries, moralities, or miracle plays. It took its rise about the same time as the opera, from which it differs chiefly in that it affords an opportunity for the highest developments of the contrapuntal art, whereas the opera is essentially monodic. The oratorio has not gone through the manifold changes and diversities that have marked the development of the opera, nor has it attracted anything like the number of composers that have devoted themselves to the opera. The first writer of any prominence in this field was Carissimi. He was followed by A.
Scarlatti; then Händel appeared and stamped for all time the form of the oratorio. His great contemporary, Bach, equaled, if he did not surpass him, but in a different style. Händel has had but two successors worthy to be named with him, - Haydn and Mendelssohn, each of whom has stamped a new character on the oratorio without descending from the high plane on which this class of composition should stand.
The taste for the oratorio seems to be on the wane, as no composer of any mark has of late years devoted his attention to it.
Orchestra, Orchestre (Fr.), Orchester (Ger.) [from Gr., orchester, a dancer].
Originally the place where the dancing took place in the Greek theatre. (1) The place where the instrumentalists are placed. (2) The company of instrumentalists. (3) The collection of instruments used at any performance. See Instrument.
Orchestrate. orchestra.
To write music for the Osgood, Emma A. Soprano; U. S. A.
B.
Otto, Ernst J. Composer; Germany. B. 1804; d. 1877.
OSTINATO