The Ride of Oromë

The stars were young upon the heaven's dome
and darkness dwelt under the shade of trees
and in the darkness evil creatures roamed,
when a horn sounded clear and pure in breeze.

Like thunder rode there Béma on his steed
and Nahar's mane shone bright with silver light:
glistening dream, the music of his feet,
before them fled the creatures of the night.

Now hoofbeats silenced, Béma rides no more
in Middle-earth under the rays of Sun,
but Nahar's children still stay on this shore
and on the grass of Rohan freely run.

The lords of horses, Mearas free and strong,
the steeds of kings that came out of a song.

For the B2MeM prompts:
O68: Oromë: ... makes the horses of Rhovanion (Powers of the World)
O67: sonnet (Poetic forms)
B10: history through songs (Forth Eorlingas!)
B10: Nothlir (family line (esp. as family tree, genealogical tree) (Quenya and Sindarin) - if family lines of horses count as well :D

(Béma was the name used for Oromë by the Rohirrim)