Elu Thingol was the King of Doriath and High King of the Sindar in the First Age. Thingol was the Sindarin form of an epithet of Elu. Elu comes from Elwë, "Star-man" (man in the sense male, not human). Thingol comes from sindacollo, "grey cloak". The Quenya form of the same name is Elwë Singollo, the latter again meaning "Graycloak". He was a good friend of Finwë, High King of the Ñoldor.
Thingol wed Melian the Maia and with her established the realm of Doriath, with their seat at Menegroth, crafted with the aid of dwarves of Belegost. Lúthien Tinúviel was their daughter. It was Thingol who set Beren on the Quest for the Silmaril, reluctant to allow his daughter's marriage to a mortal man. Beren and Lúthien were ultimately successful, and Thingol kept the Silmaril in Menegroth when they removed far to the south. Much later, he desired to have the jewel set in a necklace and hired dwarven craftsmen to do this. Everyone involved soon wanted the Silmaril for themselves, and fighting erupted over it. Menegroth was sacked and Thingol was slain.