Trio Sonata No. 1 in E Flat Major

The Trio Sonata in E flat major, BWV 525 (also known as Sonata No. 1 for organ or Trio Sonata No. 1) by Johann Sebastian Bach is part of a collection of six trio sonatas for organ, BWV 525-530. These works represent one of Bach's most outstanding contributions to the organ repertoire, adapting the Italian trio sonata genre (typically for two upper melodic instruments and basso continuo) to a single instrument: the organ, with two manuals and obbligato pedal.

The collection BWV 525-530 was compiled in Leipzig between approximately 1727 and 1730 (some sources indicate as late as 1732). Bach's autograph manuscript dates from this period. Some individual movements may come from earlier compositions (transcriptions or reworkings of cantatas, organ works or chamber music), but the sonata BWV 525 as such is considered part of this late compilation in Leipzig.

They are not linked to a specific liturgical occasion (unlike many cantatas). Bach compiled them mainly for his eldest son, Wilhelm Friedemann Bach, who was around 20 years old at the time, so that he could practise and perfect his organ technique. They are considered among Bach's most difficult and mature works for organ, focusing on technical and polyphonic mastery of the instrument rather than everyday liturgical use.

Structure of the work

Sonata BWV 525 consists of three movements, following the classical Italian model of sonata da chiesa (without dance):

1. (Allegro moderato) – Energetic and contrapuntal opening movement.
2. Adagio – Slow central movement, more expressive and lyrical.
3. Allegro – Fast and virtuosic finale.

Each movement is written in strict tripartite form: three independent voices (two upper voices on different manuals and one on the pedal), maintaining a clear and balanced texture.

Instrumentation

• Organ with two manuals (right and left for the two upper melodic voices) and obbligato pedal (for the bass voice).
• There are no other instruments; the work is conceived exclusively for organ, simulating the ensemble of a chamber trio sonata (two violins or flutes + basso continuo) through the independence of the parts.