§ Of Beren and Lúthien The Silmarillion

But Daeron the minstrel also loved Lúthien, and he espied her meetings with Beren, and betrayed them to Thingol. Then the King was filled with anger, for Lúthien he loved above all things, setting her above all the princes of the Elves; whereas mortal Men he did not even take into his service. Therefore he spoke in grief and amazement to Lúthien; but she would reveal nothing, until he swore an oath to her that he would neither slay Beren nor imprison him. But he sent his servants to lay hands on him and lead him to Menegroth as a malefactor; and Lúthien forestalling them led Beren herself before the throne of Thingol, as if he were an honoured guest.