The career of prolific Armenian pianist and composer Alexander Arutiunian [Alek’sandr Harut’unyan] spanned the Soviet age in Armenia (1920–1991), and his Trumpet Concerto (1950) achieved worldwide recognition and acclaim. Despite the importance of this work to trumpeters internationally, the information and context necessary for performers and scholars to understand Arutiunian’s Concerto and other works has not been previously available in English. Prior to this study, the composer’s biography, compositional style, and works have not been the subject of any significant published research by English-language scholars. This dissertation demonstrates that Arutiunian’s early compositional style was nurtured and influenced by the antecedents of Armenian folk music and early Armenian nationalist composers. To establish the nature of these influences, this discussion begins by exploring Armenian peasant song and professional folk-singer (ashugh) traditions, and traces the development of early Armenian nationalist composers including Komitas, Romanos Melik’yan, Aleksandr Spendiaryan, Sargis Barkhudaryan, and Aram Khachaturian. During his early schooling in the 1930s, Arutiunian studied both Armenian folk music and the music of these Armenian nationalist composers and developed a style which incorporated, emulated, and expanded on those precedents. During the 1940s, Arutiunian’s advanced training in Yerevan and Moscow led to a broadening of scope and internationalization of his style. He drew new influence from the distinct motives of Khachaturian, the Neo-Classical and modernist influence of Prokofiev, and the contrapuntal approach of Genrikh Litinsky. Following the Stalinist denunciations of 1948 (Zhdanov decree or Zhdanovshchina), Arutiunian’s Big Soviet style emerged, and is so-called because it blended his early style with the grand, dramatic, and Romantic tradition of Tchaikovsky and Rimsky-Korsakov. His first composition in this vein, Cantata About the Motherland (1948), was considerably more conservative than his other works but it so successfully fit the political requirements of Socialist Realism that it earned him the Soviet Union’s highest artistic honor, the Stalin Prize. In the wake of this achievement, Arutiunian’s Big Soviet style rapidly developed, producing major successes in his Festive Overture (1949) and Trumpet Concerto (1950). This study is based primarily on the examination of rare Soviet-era scores and recordings and the new translation of Russian- and Armenian-language primary and secondary sources, including Arutiunian’s own Memoirs (2000). The resulting descriptive and contextual analysis establishes the nature of Arutiunian’s compositional output up to 1950 and the influences that Armenian and Soviet antecedents had upon his music. It lays the foundation of background, context, and connections for performers and scholars to understand the idioms and stylistic conventions found in Arutiunian’s early works, culminating with a detailed examination of his Trumpet Concerto (1950).