Jean Sibelius (1865-1957) was a Finnish nationalist composer. He is best known for his symphonic poem Finlandia. He was initially strongly influenced by Wagnerian nationalism, but he eventually decided it was too brash and arrogant; his music tends toward the more emotional style of Tchaikovsky. Like Rachmaninoff, he was often criticized for being too conservative in his compositional style, which remained firmly tonal and Romantic while his increasingly modernist peers were experimenting with atonality (writing in no particular key) and other avant-garde techniques. He supposedly commented that while the Modernists were mixing elaborate cocktails, he served the public plain water. His incidental music to The Tempest was written at the end of his career, in 1926, after which he effectively retired from composing except for some abortive attempts to write an eighth symphony. Like Mendelssohn's Midsummer Night's Dream, it consists of a series of vocal pieces and long orchestral interludes:
I think that despite the radically different period and style, Sibelius' piece actually bears a lot of resemblance to Mendelssohn's. Both chose a comedy set in a fantastic realm, although The Tempest is rather more ambiguous, complicated, and occasionally dark. I think the biggest difference from the Mendelssohn, except for the instrumentation and other differences that inevitably occur in two pieces a century apart, is the tone of mystery and sometimes of weariness throughout the Sibelius--both pieces evoke energy and magic, but Sibelius's takes a darker turn.