Thingol haughtily refused to give Lúthien's hand in marriage. He said that he would only allow the marriage if Beren recovered one of the Silmarils, the three hallowed jewels which the Noldor Elves had lost to Morgoth, from the Iron Crown of Morgoth. The task was intended to be impossible, but Beren and Lúthien, with the aid of Finrod of Nargothrond and Huan the Great Hound (both of whom died protecting Beren), braved many perils (even besting Sauron, then Morgoth's most powerful lieutenant) and finally reached Angband and came before Morgoth. Beren was able to capture a Silmaril when Lúthien had made the Dark Lord fall asleep through her singing. He then attempted to take another Silmaril from Morgoth's crown, but the tip of his dagger Angrist broke and cut Morgoth. When they wanted to escape from Angband, the great wolf Carcharoth, whom Morgoth had bred, attacked them. Beren held out the Silmaril, hoping that its radiance would avert the beast, but he was mistaken. Carcharoth bit off his hand swallowed it and the Silmaril (thus Beren was called Erchamion, One-hand), and proceeded to run rampant through Doriath. Lúthien and the unconscious Beren were rescued by the Eagles of Manwë. They eventually returned to Thingol, where Beren claimed that he was holding the Silmaril in his hand; when he showed the king the stump of his arm, the king was moved to compassion for Beren. Beren participated in the hunting of Carcharoth, in which the beast was slain and the Silmaril recovered; the quest was accomplished, but Beren was mortally wounded.
Lúthien's love for Beren was so strong that, hearing of his death, she laid down and died. Her soul went to the Halls of Mandos, where she moved Mandos to pity through her singing. Both she and Beren were restored to life, but both of them would die the death of Men, and go beyond the walls of Arda to a place unknown. Thus Beren and Lúthien lived again, and dwelt on Tol Galen in the middle of the river Adurant in Ossiriand. There they stayed apart from other mortals; Beren was involved with the events of the First Age only one further time, when he waylaid a group of Dwarves who had destroyed Doriath and stolen the Nauglamír in which the Silmaril was set.
Lúthien bore Beren a son, named Dior, Thingol's heir, considered to be one of the fairest beings to ever live, for in him flowed the blood of Men, Elves and Maiar (Ainur). Through his descendants, the blood of Beren and of Lúthien was preserved among the Eldar and the Edain.
The animated adaptation of The Lord of the Rings includes a similar scene in which Aragorn is relating the story of Beren and Lúthien for the Hobbits, but here there is no connection made between the two to Aragorn and Arwen, since the latter does not appear.
The special extended edition of Peter Jackson's movie version of The Fellowship of the Ring (2001) contains a brief mention of the story. During the journey from Bree to Rivendell Frodo hears Aragorn singing quietly to himself one night and asks who the woman is of whom he is singing. Aragorn replies that he is singing of Lúthien. When Frodo asks what happened to her Aragorn replies, "she died". This is true enough, and can be seen as a reflection of Aragorn's concern over Arwen's renunciation of immortality for his sake.
It is widely believed that the story and the characters were largely inspired by the young Tolkien's romance with Edith Bratt, his future wife, who danced for her husband in the woodland glade.
The surname Tolkien derives from the German Toll-kühn meaning "Foolishly brave" The name Beren also means "brave" in Sindarin and some believe that this is intentional by the author.
The tale of Beren and Lúthien also shares an element with folktales such as the Welsh Culhwch and Olwen and others— namely, the disapproving parent who sets a seemingly impossible task (or tasks) for the suitor, which is then fulfilled.
It may also have real-life parallels: some sources indicate that Edith's Protestant family strongly disapproved of Tolkien's Catholic Faith. In addition, Tolkien's guardian, a priest of the Birmingham Oratory, forbade him from having any contact with Edith until he turned 21. Tolkien's guardian clearly feared that his young charge was in danger of losing the Faith. Tolkien obeyed to the letter, but telegraphed Edith on his 21st birthday. Although she was engaged to another man, she returned the ring and announced her engagement to Tolkien instead.
After Edith's death, Tolkien had her headstone engraved EDITH MARY TOLKIEN Lúthien 1889 – 1971, and when he died two years later he left orders for his own name to be written JOHN RONALD REUEL TOLKIEN Beren 1892 – 1973