Harmonic minor keys are used when writing chords. There is another version of the minor key known as the melodic minor. This is used when writing a melody. Each key signature has two possible keys.

The dominant seventh of a V chord can be shown by the symbol V7. For example, G7 is made by taking the major triad of G (G - B - D ... cadence of a piece in a minor key ends with a major chord ...

Schubart was a forefather of musical category creation: In his 1784 essay “A History of Key Characteristics ... emotions to other minor keys such as A minor, E minor and B minor.