In his Sonata No. 4 in A minor of 1876, Rheinberger crafts a sonata in three contrasting and architecturally balanced movements, based on a Gregorian psalm-tone. In the first movement, statements of the principal theme alternate with variations on the tonus peregrinus, ending with a virtuosic triplet figure and large chords. The second movement is an A-B-A form; a graceful, vocal idiom. A second theme, in quavers, is accompanied by semiquaver figures. Erudite but subtle modulations typify the harmony in this movement. The concluding fuga chromatica is austere, yet intricate. Rheinberger, after an extended pedal-point on E, restates the first movement's principal theme, then closes this sonata with a highly chromatic peroration on the tonus peregrinus and VII7-I final cadence.