§ Of the Beginning of Days The Silmarillion

It is told among the wise that the First War began before Arda was full-shaped, and ere yet there was any thing that grew or walked upon earth; and for long Melkor had the upper hand. But in the midst of the war a spirit of great strength and hardihood came to the aid of the Valar, hearing in the far heaven that there was battle in the Little Kingdom; and Arda was filled with the sound of his laughter. So came Tulkas the Strong, whose anger passes like a mighty wind, scattering cloud and darkness before it; and Melkor fled before his wrath and his laughter, and forsook Arda, and there was peace for a long age. And Tulkas remained and became one of the Valar of the Kingdom of Arda; but Melkor brooded in the outer darkness, and his hate was given to Tulkas for ever after.