All I know is a door into the dark.
Outside, old axles and iron hoops rusting;
Inside, the hammered anvil's short-pitched ring,
The unpredictable fantail of sparks
Or hiss when a new shoe toughens in water.
The anvil must be somewhere in the centre,
Horned as a unicorn, at one end and square,
Set there immoveable: an altar
Where he expends himself in shape and music.
Sometimes, leather-aproned, hairs in his nose,
He leans out on the jamb, recalls a clatter
Of hoofs where traffic is flashing in rows;
Then grunts and goes in, with a slam and flick
On a practical level the blacksmith/poet isn’t a romantic figure.  Heaney moves from flights of imagination — the religious alter and the unicorn —  to reality. His subject, the two blended characters who create metal artefacts and spectacular poetry, are ordinary men.
The Forge