The Valar (singular Vala) are characters in J. R. R. Tolkien's legendarium. They are first mentioned in The Lord of the Rings, but The Silmarillion (published posthumously but assembled mostly from material written before The Lord of the Rings) develops them into the Powers of Arda or the Powers of the World. They are angelic powers, the Ainur that chose to go into the World (Arda) and complete its material development after its form was determined by the Music of the Ainur (Ainulindalë).