The Story of Kullervo
In a 1914 letter to Edith Bratt, Tolkien mentions that he is "trying to turn one of the stories [from the Kalevala] — which is really a very great story and most tragic – into a short story". Humphrey Carpenter notes that "'The Story of Kullervo', was never finished, but proved to be the germ of the story of Túrin Turambar in The Silmarillion".
"The germ of my attempt to write legends of my own to fit my private languages was the tragic tale of the hapless Kullervo in the Finnish Kalevala. It remains a major matter in the legends of the First Age (which I hope to publish as The Silmarillion)"― J.R.R. Tolkien, Letter 257
 See also