Morgan was a composer, best known for his
hymns and
fuguing tunes. While not so famous as those by
William Billings, his works share the same characteristic roughness, directness, and folk-like simplicity. Publications containing his work include
The Federal Harmony (New Haven, 1790), and
The Philadelphia Harmony, 4th ed. (Philadelphia, 1791). The former collection includes what perhaps is his most famous composition entitled, "Amanda," a setting of
Isaac Watts's poem based on Psalm 90. This hymn was the basis for a classical work written by American composer
Thomas Canning in 1946, "Fantasy on a Hymn Tune by Justin Morgan." The tune "Despair," in the 1791 collection, cites the death of "Amanda" (referring to his wife, Martha Day, who died on March 20 that year, ten days after giving birth to their youngest daughter, Polly) in a paraphrase of
Alexander Pope's
Ode on Solitude. Morgan's setting of Psalm 63, entitled
Montgomery, was a popular
fuguing tune, included among the 100 hymn-tunes most frequently printed during the eighteenth century. three more songs, including "Amanda" and "Despair," both grieving over the death of his wife, are in the
Shenandoah Harmony. Its voice-leading, as is common in works by
early American composers, contains numerous unabashed parallel fifths, giving the music a folk-like quality. Another work of his, the
Judgment Anthem, is tonally adventurous, moving back and forth between E minor and E♭ major; it was the first anthem published in
shape notes, appearing in Little and Smith's
The Easy Instructor (1801), and many tunebooks thereafter. ==In literature==