Were Beren and Luthien alive during the First Age? Second Age? Or before? Because I was interested in knowing, because when Aragorn sang about them in Fellowship of the Ring I was curious.
Luthien was born in Doriath in the years of the Trees before the Sun first rose. Beren lived about 400 years after the Sun first rose in the First Age, which would have been about 6000 years before the events of The Lord of the Rings.
They both died, and were allowed to return to Middle-Earth by Mandos. But then Luthien, who was an elf, was made into a mortal, and they both died permanently late in the First Age.
The Tale of Beren and Lúthien is the story of the love and adventures of the mortal Man, Beren and the immortal Elf-maiden, Lúthien, as told in several works of J.R.R. Tolkien. Their adventures took place in the First Age of Arda after the rising of the Sun and the Moon.
The human Beren Erchamion was born in the Years of the Sun in the First Age 432. REF: The War of the Jewels: "The new genealogies of the Edain", p. 229–38.
The elven maiden, Lúthien Tinúviel was born in the First Age in the year 4700 around 300 years before the rising of the Sun and the Moon.
The Lay of Leithian is the unfinished poem of J.R.R. Tolkien. It tells the Tale of Beren and Lúthien, the story of the love of the mortal Man Beren and the immortal Elf maiden Lúthien. The poem consists of over 4200 verses. It was published after Tolkien's death in The Lays of Beleriand.
See: The Timeline of Arda
History of the Lay of Lethian
The first version of the story is the Tale of Tinúviel, which was written in 1917 as a part of The Book of Lost Tales. During the 1920s Tolkien started to reshape the tale and to transform it into an epic poem which he called The Lay of Leithian. He never finished it, leaving three of seventeen planned cantos unwritten.
After his death The Lay of Leithian was published in The Lays of Beleriand, together with The Lay of the Children of Húrin and several other unfinished poems. The latest version of the tale is told in prose form in one chapter of The Silmarillion and is recounted by Aragorn in The Fellowship of the Ring. Furthermore it was the model for The Tale of Aragorn and Arwen, which is told in the appendices of The Lord of the Rings.