Subject

What it means

The subject is the theme of a fugue — the melodic idea that sounds at the beginning in one voice alone and is then taken up in turn by all the other voices. The whole movement rests on it; its properties determine what is possible in the course of the piece.

Musical use

A good fugue subject combines distinctness with workability. It must be recognizable in every voice and register, and it must be able to combine with countersubjects. It often consists of a striking head that makes it recognizable, and a continuing tail that leads over to the next voice. Its length reaches from a few notes to several bars; the older Italian theory distinguished various types by length and character.

The second voice brings the theme as the answer, usually at the level of the dominant. If the answer is an exact transposition, it is called real; if it is slightly altered to stay within the key — usually at the point where tonic and dominant meet — it is called tonal. The countervoice accompanying the theme at its entries is called the countersubject, if it is retained.

In the course of the fugue, the subject can be transformed: inverted, augmented, diminished, in retrograde, and combined with itself in stretto. These possibilities depend on its construction, which is why fugue subjects were often invented with such procedures in mind.

The subject is to be distinguished from the theme in sonata form, which is broken down and worked motivically, while the fugue subject usually recurs as a whole.

In Latin terminology, the theme in its basic shape is called the dux, the leader. The comes answers it, the theme at the dominant. It should be memorable and contrapuntally workable. In English it is called the subject.

Performance practice

Impress the subject on yourself so that you recognize it immediately in every voice. Mark all the entries and make them audible, especially in middle voices. And shape the head distinctly — it is the hallmark.