1. La Breve tenía el doble de duración de la semiBreve

2. A quarter note (American) or Crotchet (British) is a note played for one quarter of the duration of a whole note (or semibreve)

3. In music, a double whole note (American), Breve (British), or double note is a note lasting two times as long as a whole note (or semiBreve)