Hector Berlioz (1803-1869) was a French composer, conductor, and music critic, known for his pioneering contributions to Romantic music. His work is characterized by innovative orchestration, emotional expressiveness, and dramatic narrative structures. Berlioz's genre spans primarily orchestral and operatic music, with a strong affinity for programmatic compositions. Notable works include the symphonic poem "Symphonie fantastique" (1830), which vividly depicts an artist's descent into despair and obsession, and "Harold en Italie" (1834), a symphony featuring a solo viola. His opera "Les Troyens" (1863), based on Virgil's "Aeneid," is considered one of his masterpieces, blending grand choral and orchestral forces. Berlioz's impact on music is profound; he expanded the possibilities of orchestration and narrative in concert music, influencing later composers like Richard Wagner and Gustav Mahler. His theoretical writings, particularly "Treatise on Instrumentation," laid the groundwork for modern orchestration techniques. Berlioz's embrace of literary themes in music helped pave the way for the programmatic trends that would dominate the late 19th and early 20th centuries, solidifying his status as a key figure in the evolution of Western classical music.