Hector Berlioz (December 11, 1803 – March 8, 1869) was a French Romantic composer, best known for his compositions Symphonie fantastique and Grande messe des morts (Requiem). Berlioz made significant contributions to the modern orchestra with his Treatise on Instrumentation. He specified huge orchestral forces for some of his works; as a conductor, he performed several concerts with more than 1,000 musicians. He also composed around 50 songs. His influence was critical for the further development of Romanticism, especially in composers like Richard Wagner, Nikolai Rimsky-Korsakov, Franz Liszt, Richard Strauss, Gustav Mahler and many others.
Hector Berlioz was born in France at La Côte-Saint-André in the département of Isère, near Grenoble. His father, a respected provincial physician and scholar, was responsible for much of the young Berlioz's education.
Berlioz was not a child prodigy, unlike some other famous composers of the time; he began studying music at age 12, when he began writing small compositions and arrangements. As a result of his father's discouragement, he never learned to play the piano, a peculiarity he later described as both beneficial and detrimental. He became proficient at guitar, flageolet and flute. He learned harmony by textbooks alone—he was not formally trained.
In March 1821, he graduated from high school in Grenoble, and in October, at age 18, Berlioz was sent to Paris to study medicine, a field for which he had no interest and, later, outright disgust after viewing a human corpse being dissected. (He gives a colorful account in his Mémoires.) He began to take advantage of the institutions he now had access to in the city, including his first visit to the Paris Opéra.
He also began to visit the Paris Conservatoire library, seeking out scores of Gluck's operas and making personal copies of parts of them. He recalled in his Mémoires his first encounter with Luigi Cherubini, the Conservatoire's then music director. Cherubini attempted to throw the impetuous Berlioz out of the library since he was not a formal music student at that time.
Despite his parents' disapproval, in 1824 he formally abandoned his medical studies to pursue a career in music.