In 1889 Sibelius traveled to Berlin to study counterpoint with Albert Becker, where he also was exposed to new music, particularly that of Richard Strauss. In Vienna he studied with Karl Goldmark and then Robert Fuchs, the latter said to be his most effective teacher. Now Sibelius began pondering the composition of the Kullervo Symphony, based on the Kalevala legends. Sibelius returned to Finland, taught music, and in June 1892, married Aino Järnefelt, daughter of General Alexander Järnefelt, head of one of the most influential families in Finland. The premiere of Kullervo in April 1893 created a veritable sensation, Sibelius thereafter being looked upon as the foremost Finnish composer. The Lemminkäinen suite, begun in 1895 and premiered on April 13, 1896, has come to be regarded as the most important music by Sibelius up to that time. In 1897 the Finnish Senate voted to pay Sibelius a short-term pension, which some years later became a lifetime conferral. The honor was in lieu of his loss of an important professorship in composition at the music school, the position going to Robert Kajanus. The year 1899 saw the premiere of Sibelius' First Symphony, which was a tremendous success, to be sure, but not quite of the magnitude of that of Finlandia (1899; rev. 1900). In the next decade Sibelius would become an international figure in the concert world. Kajanus introduced several of the composer's works abroad; Sibelius himself was invited to Heidelberg and Berlin to conduct his music. In March 1901, the Second Symphony was received as a statement of independence for Finland, although Sibelius always discouraged attaching programmatic ideas to his music. His only concerto, for violin, came in 1903. The next year Sibelius built a villa outside of Helsinki, named "Ainola" after his wife, where he would live for his remaining 53 years. After a 1908 operation to remove a throat tumor, Sibelius was implored to abstain from alcohol and tobacco, a sanction he followed until 1915. It is generally believed that the darkening of mood in his music during these years owes something to the health crisis.
Sibelius made frequent trips to England, having visited first in 1905 at the urging of Granville Bantock. In 1914 he traveled to Norfolk, CT, where he conducted his newest work The Oceanides. Sibelius spent the war years in Finland working on his Fifth Symphony. Sibelius traveled to England for the last time in 1921. Three years later he completed his Seventh Symphony, and his last work was the incidental music for The Tempest (1925). For his last 30 years Sibelius lived a mostly quiet life, working only on revisions and being generally regarded as the greatest living composer of symphonies. In 1955 his 90th birthday was widely celebrated throughout the world with many performances of his music. Sibelius died of a cerebral hemorrhage in 1957.