§ Of the Return of the Noldor The Silmarillion

Now the flames of that burning were seen not only by Fingolfin, whom Fëanor had deserted in Araman, but also by the Orcs and the watchers of Morgoth. No tale has told what Morgoth thought in his heart at the tidings that Fëanor, his bitterest foe, had brought a host out of the West. It may be that he feared him little, for he had as yet no proof of the swords of the Noldor; and soon it was seen that he purposed to drive them back into the sea.