En Saga Op.9 is a tone poem for orchestra, and is one of the composer's earliest orchestral works, filled with youthful dynamism and energy. It is also highly atmospheric, clearly evocative of the composer's beloved Finland – its people, proud history, countryside and landscapes. The title translates as the Swedish (rather than Finnish) for A Fairy Tale, suggesting a programmatic work, but, despite there seeming to be a 'story' present, the composer never identified any specific extra-musical inspiration.
The work was originally composed in 1892, but not to great success. However, the composer later revised the work in 1902, shortly after having composed the Symphony No.2, when it received the acclaim it deserved.
Available here is a study score of Sibelius' tone poem En Saga Op.9, which is ideal for study and perusal usage.