Fuga on a theme of Arcangelo Corelli (1653-1713) in h-moll / B minor BWV 579.
The date of composition here is uncertain, though the high quality of the work suggests Bach had already attained a mastery of the fugue form. Thus, it probably dates at least to the early years of the composer's Weimar period (1708 - 1717), during which he was the court organist in the service of the Duke of Sachsen-Weimar. In this Fugue in B minor, he uses a theme by Italian composer Arcangelo Corelli, who gave it a vigorous (Allegro) treatment. Bach, on the other hand, slows the tempo and imaginatively alters its character, converting its vivacity to a slightly melancholy deliberateness. Bach presents Corelli's theme in a somber dressing at the outset, the pacing leisurely, the textures light.