Jean Sibelius was born in Hämeenlinna in the province of Tavastehus, Finland on December 8, 1865.
He studied in Helsinki from 1886 with Wegelius, also gaining stimulus there from Busoni, though at the same time he fostered ambitions as a violinist. In 1889 he went to Berlin to continue his composition studies with Becker, then after a year to Vienna under Goldmark and Fuchs. He returned to Helsinki in 1891 and immediately made a mark with his choral symphony Kullervo, though it took him another decade to establish a wholly consistent style and to emerge from the powerful influence of Tchaikovsky: important stages on the journey were marked by the Karelia suite, the set of four tone poems on the legendary hero Lemminkäinen (including The Swan of Tuonela), the grandiose Finlandia and the first two symphonies.
As these titles suggest, he was encouraged by the Finnish nationalist movement (until 1917 Finland was a grand duchy in the Russian empire), by his readings of Finnish mythology (Kullervo and Lemminkäinen are both characters from the Kalevala, which was to be the source also for subjects of later symphonic poems) and, in some degree, by the folk music of Karelia. But the most important stimulus would seem to have been purely musical: a drive towards continuous growth achieved by means of steady thematic transformation, and facilitated by supporting the main line very often with highly diversified ostinato textures instead of counterpoints. The singleness of purpose also has to do with the frequently modal character of Sibelius' harmony.
The Violin Concerto of 1903 was effectively a farewell to 19th-century Romanticism, followed by a pure, classical expression of the new style in the Symphony No. 3. This was also a period of change in his personal life. In 1904 he bought a plot of land outside Helsinki and built a house where he spent the rest of his life with his wife and daughters. Also, his music gained a large international following, and he visited England, (four times in 1905-12) and the United States in 1914. Symphony No. 4, with its conspicuous use of the tritone and its austere textures, took his music into its darkest areas; No. 5 brought a return to the heroic mould, developing the process of continuous change to the extent that the first movement evolves into the scherzo.
But that work took him some time to get right, written in 1915, it was revised in 1916 and again in 1919, and after World War I he produced only four major works: the brilliant and elusive Symphony No. 6; No. 7, which takes continuity to the ultimate in its unbroken unfolding of symphonic development; the incidental music for The Tempest; and the bleak symphonic poem Tapiola. He lived for another three decades, but published only a few minor pieces; an eighth symphony may possibly have been completed and destroyed. His reputation, however, continued to grow, and his influence has been profound, especially on Scandinavian, English and American composers, reflecting both the traditionalism and the radical elements in his symphonic thinking.
Sibelius died in Järvenpää, Finland September 20, 1957.
Source: The Gove Concise Dictionary of Music