We have no specific dates for Beregar's birth and death, but we know that he lived during the eighth and ninth centuries of the Second Age. His daughter Erendis was born in II 771, so this is the earliest definite date we can give him. From this point, he is mentioned several times through the account of Aldarion and Erendis, with his last appearance in the story relating to events of the year II 877.

Beregar's name is not explained, but it was perhaps related to Bereg, the name of an early member of the House of Bëor. That name (and others in the family line, such as that of Beregar's own ancestor Bregolas) seem to have been at least influenced by the Elvish root berék-, meaning 'wild, sudden, fierce'.

Beleth is not mentioned in The Silmarillion, but she is shown in the extended genealogy of the House of Bëor in volume XI of The History of Middle-earth. A period of at least three centuries separated Beleth and Beregar, so Beleth must have had several generations of descendants living through the end of the First Age and then establishing themselves in Númenor.

Beleth is briefly mentioned in Unfinished Tales, but there her name is given incorrectly as 'Bereth'. This confusion of names is resolved by Christopher Tolkien in his notes to the genealogy mentioned above.