Lament for the Rohirrim is sung by Aragorn as he, Gandalf, Legolas, and Gimli approach Edoras. He originally chants it in the language of Rohan, then translates it for Gimli and Legolas. A poet in Rohan originally wrote it about Eorl the Young and his horse Felaróf.
Where now the horse and the rider? Where is the horn that was blowing?
Where is the helm and the hauberk, and the bright hair flowing?
Where is the hand on the harpstring, and the red fire glowing?
Where is the spring and the harvest and the tall corn growing?
They have passed like rain on the mountain, like a wind in the meadow;
The days have gone down in the West behind the hills into shadow.
Who shall gather the smoke of the dead wood burning,
Or behold the flowing years from the Sea returning?