Jean Sibelius was a Finnish composer who lived from 1865 to 1957. He is considered one of the most influential composers of the late 19th and early 20th centuries, and his works are still performed today. He is best known for his symphonies, concertos, and tone poems, which often feature themes inspired by Finnish mythology and nature. He also wrote several operas, choral works, and chamber music. His music has been described as having a unique combination of romanticism and nationalism.