Kalevala influenced The Silmarillion

Tolkien read the Kalevala in Finnish as a student and began retelling its Kullervo cycle in 1914, the first of his legends. Kullervo, the doomed son who unknowingly seduces his sister and dies by his own sword, became Túrin Turambar, and Tolkien said the Kalevala set him on the road to making a mythology of his own.