Belen was the younger son of Balan and his husband Bemen. Born in the lands that would later be known as Eriador, he journeyed westward across the Blue Mountains with his family in search of safer lands. The crossing was treacherous, and young Belen, only sixteen years old, nearly died when a stone beneath his feet gave way to empty air. He was rescued by his father Bemen, who lifted him to safety before he, too, lost contact with the ground and fell to his death.
Bemen was deeply mourned by his kin, Belen most of all, but Balan determined to press forward across the mountains. Eventually they arrived in Beleriand, where they discovered strange elves who shone with the Light of the Gods. Balan quickly became enamoured of one such elf, Finrod Felagund, and entered into Felagund’s service, leaving his family and people for the elf’s kingdom of Nargothrond. At this time, Belen’s brother Baran took up leadership in their father’s stead, naming their people the House of Bëor, for all believed Balan to have sworn vassalage to Felagund.
Belen grew in the shadow of his brother, and was fiercely loyal to Baran for all his life. When he came of age, he took the hunter Talag as his spouse, and together they had one child, Beldir, among the first of Bëor’s folk to be named in the Sindarin tongue of the elves. Beldir grew into a cunning hunter like Talag his parent, wedding a cheerful woman known as Meren and producing a son of his own, Belemir.