However, the true dangers of the oath became apparent when the lovers Beren and Lúthien recovered one of the jewels from Morgoth, which ultimately came into the possession of Dior, their son, who succeeded his grandfather Thingol as ruler in Menegroth. The presence of the Silmaril awoke the oath and caused the Sons of Fëanor to make war on the Elves of Doriath when Dior refused to yield the jewel. The brothers killed Dior and sacked the halls of the Sindar, committing the second Kinslaying, where three of their number—Celegorm, Curufin, and Caranthir—died. However, the Silmaril escaped the destruction of Doriath and the oath drove the remaining sons onwards. When the Sons of Fëanor later learned that it was possessed by Elwing daughter of Dior, who dwelt near the mouths of Sirion together with survivors from Doriath and the city of Gondolin, they attacked after Elwing also refused to return the Silmaril to them, committing the third and final Kinslaying where Amras was slain.