This study analyzes the music theory within Julia Ward Howe’s “Battle Hymn of the Republic” (1862) with an aim to highlight the impact of the song’s musical structure on its historical significance. Much of the existing scholarly conversation surrounding the hymn places an emphasis on its lyrics while disregarding its musical structure. Utilizing the work of scholars such as music historian Elizabeth Morgan, cognitive scientist Steven Pinker, philosopher Alain de Botton, and historian David S. Reynolds, resulted in an interdisciplinary chord analysis of the song. The analysis reveals inherently simple and stable patterns comprised of mainly IV and V chords, resolved by a Perfect Authentic Cadence (PAC). Attributed to original composer William Steffe, the chord progressions and phrase endings on a PAC indicate that the simplicity and finality of the tune may have appealed to listeners struggling to find stability in their everyday lives. Prior to Howe’s lyrics, Steffe’s original tune, John Brown’s Body (ca. 1850), was a popular American folk song. During the American Civil War, Howe’s lyrics repurposed Steffe’s composition as a patriotic anthem for the Union Army. The use of a familiar tune with such polarizing lyrics depicts the heightened tension between the Union and Confederate armies. Findings within this study conclude that rather than solely analyzing historically significant events in a traditional, “textbook” manner, music provides additional and valuable insight for the study of social attitudes and perceptions. This research suggests the use of music analysis as a lens through which to contextualize the innately qualitative features of history.