The Finlandia composer is Jean Sibelius, an 8-letter answer to the crossword. Sibelius was a Finnish composer and violinist who lived from 1865 to 1957. He is widely recognized as one of the most important composers of the late 19th and early 20th centuries, and his works are still performed today. His most famous composition is the symphonic poem Finlandia, which has become a symbol of Finnish national identity.