The sword Anglachel was forged anew for him by cunning smiths of Nargothrond, and though ever black its edges shone with pale fire; and he named it Gurthang, Iron of Death. So great was his prowess and skill in warfare on the confines of the Guarded Plain that he himself became known as Mormegil, the Black Sword; and the Elves said: 'The Mormegil cannot be slain, save by mischance, or an evil arrow from afar.' Therefore they gave him dwarf-mail, to guard him; and in a grim mood he found also in the armouries a dwarf-mask all gilded, and he put it on before battle, and his enemies fled before his face.
J.R.R. Tolkien: The Silmarillion: Chapter 21: Of Túrin Turambar