During the transition to his heroic period, Ludwig van Beethoven employed Classical era ideas in an experimental way that led to the discovery of his personal style. Beethoven's transition to the heroic style was marked by desire to compose music in what he referred to as a "new way." The refinement of his novel and complex heroic style occurred through technical experimentation with an idea known in this thesis as the Eroica Theme. In Opus 43, Die Geschöpfe des Prometheus, WoO 14, Zwölf Contretänze für Orchester, Opus 35, Fünfzehn Variationen (Es-dur) mit einer Fuge für Klavier, and Opus 55, Symphonie Nr. 3, "Sinfonia eroica," Beethoven built upon and expanded this idea to test the limits of its structural potential as symphonic material. Beethoven's use and manipulation of the Eroica Theme provides us with insight into the compositional process through which Beethoven developed his signature heroic style.