But Roman, when thou standest Upon that holy ground, Look thou with heed on the dark rock That girds the dark lake round. So shalt thou see a hoof-mark Stamped deep into the flint： It was not hoof of mortal steed That made so strange a dint： There to the Great Twin Brethren Vow thou thy vows, and pray That they, in tempest and in flight, Will keep thy head alway.