Kullervo began as an Overture in E major that Sibelius wrote in 1890 as a student in Vienna. To his future wife Aino he wrote of possibly a "symphony, in three or perhaps four movements" based on the folk epic Kalevala, collected by Elias Lönrott in 1835, expanded in 1849 from 32 runos to 50, and republished in 1890. Though Sibelius later denied it, he heard a rune-singer from Karelia during the summer of 1891; inspired by her repertory of orally preserved folk music, he began to evolve a personal style. By 1892, he had completed Kullervo, a work in five movements of 72 minutes' total duration, which he introduced in Helsinki on April 28. He called it his Op. 7, yet never allowed publication of it in his lifetime. With soprano and baritone soloists, male chorus, and orchestra, it has been identified variously as a symphony, a symphonic poem, even a cantata, but it is in fact a conflation of all three -- and startlingly anticipatory in "Kullervo and his Sister," the long central movement.
The protagonist didn't materialize until 1849, as the subject of Runos 31-36: the bastard child of a pregnant housemaid, who survived a massacre by Kullervo's evil uncle. Despite attempts to destroy the child (by drowning, immolation, and finally hanging), Kullervo survives. Brain-damaged, however, he does all manner of wickedness in return to the uncle's cruel wife and properties. Hearing that his parents and three siblings survived the massacre, he finds all of them in the northland, except for a roving sister. Despite their happy reunion, Kullervo wrecks whatever he puts his hand to, and is finally sent off to pay taxes. On the journey back he encounters a maiden who resists his advances, but eventually succumbs to the warmth of his fur-lined sleigh. After they've cohabited, Kullervo discovers the woman is the missing sister, who in shame and despair drowns herself. Unbalanced by guilty rage, Kullervo declares war on his evil uncle. With a magic sword given to him by the god Ukko, he destroys everything and everyone, returns to where his sister drowned, and falls on the sword.
The opening "Introduction" is putatively a portrait of Kullervo. But while this Lisztian mélange in sonata form has a notable second theme, hardly anything truly Sibelian appears until the second movement, "Kullervo's Youth," with its distinctive main subject in the oral runic style. The work becomes suddenly epic in the central movement, narrated mostly by the chorus with the soloists as incestuous siblings, and which concludes starkly with the protagonist's lamentations. Next comes "Kullervo Goes the Battle," which sounds stylistically second-hand after the preceding movement. In "Kullervo's Death," the chorus sings the conclusion of Runo 36 verbatim. It doesn't quite rise to the heights of the third movement, yet is fittingly somber and ends as the work began, in E major.