The Silmarillion

The Silmarilli were three perfect jewels, fashioned by Fëanor, most gifted of the Elves, and within them was imprisoned the Last of the Two Trees of Valinor. When the first Dark Lord, Morgoth, stole the jewels and set them within an iron crown in the impenetrable fortress of Angband, Fëanor and his kindred took up arms against the great Enemy and waged a long and terrible war to recover them. 'The Silmarillion' tells the story of the rebellion by Feanor's allies against the gods, their exile from Valinor and return to Middle-earth.