Grove's dictionary of music and musicians

SUBJECT SUBJECT 731
hymnologists, though it was not until the close
of the 15th, or beginning of the 16th century
that it developed itself in Germany into the
perfectly rhythmic and metrically regular melody
of the Chorale.i
Upon a phrase of this plain-song the inventors
of harmony discoursed at will ; in other words,
they treated it as a Subject. Composers of the
11th century discoursed upon it by singing a
second part against the given Subject, in plain
counterpoint—note against note.^ They sang
this part extempore ; and, because it was sung
by a second voice, it was called Uiscantus—the
literal meaning of which is, a song sung by two
voices. See Disca>jt.
When extempore discant gave place to written
counterpoint, the C3Tw