The Valar , aware of the risk Melkor posed to the Elves , attacked him in Utumno , and after a long siege , Melkor and his forces were defeated , and Melkor was taken prisoner to Valinor to serve '' three ages '' in the Halls of Mandos .
The Valar , aware of the risk Melkor posed to the Elves , beleaguered him in Utumno . 
 After a long siege , Melkor and his forces were defeated , and Melkor was taken prisoner to Valinor to serve '' three ages '' in the Halls of Mandos .