Gil-galad was an Elven-king.
Of him the harpers sadly sing:
the last whose realm was fair and free
between the Mountains and the Sea.His sword was long, his lance was keen,
his shining helm afar was seen;
the countless stars of heaven’s field
were mirrored in his silver shield.But long ago he rode away
and where he dwelleth none can say;
for into darkness fell his star
in Mordor where the shadows are.J.R.R. Tolkien (1892-1973) English writer, fabulist, philologist, academic [John Ronald Reuel Tolkien]
The Lord of the Rings, Vol. 1: The Fellowship of the Ring, Book 1, ch. 11 “A Knife in the Dark” [Sam] (1954)
(Source)
Sam says he was taught it by Bilbo, who claimed to have written it. Aragorn corrects him, saying it is part of a lay called "The Fall of Gil-galad," though Bilbo appears to have translated it from the Elvish.