Haydn Ensemble
One of the representative genres of music from the 17th century and the first half of the 18th century was the trio sonata. The term “trio” does not mean that these works were intended exclusively for three instruments; the point was the combination of two treble (melodic) voices in conjunction with a basso continuo section. The basso continuo usually required a keyboard (or other harmonic) instrument and a viola da gamba, so there could be more than three performers. Jan Dismas Zelenka did indeed label his compositions as Sonatas for Two Oboes and Continuo, but in essence they were a type of trio sonata. Johann David Heinichen and Johann Friedrich Fasch used the standard genre classification.