More malignant in character was the Shirt of Nessus as the source of misfortune from which there was no escape. According to tradition, Nessus the Centaur, while conveying Dejanira across a river, was shot by Hercules for his rudeness. The dying Centaur bequeathed his tunic to Dejanira, assuring her that to whomsoever she gave it, they would love her exclusively. Believing this, she presented it to Hercules, who on wearing it was subjected to such torture that, being unable to remove the garment, he immolated himself on a funeral pyre. Similarly malignant was the poison-cloak sent as a present to Arthur by Queen Morgan la Fay. _Swords_ Swords at all times have been possessed of magical qualities, but the belief possibly indicates stages of development. The description of the sword of Perseus as a form of diamond, suggests that the story had its origin in the Stone Age. It is reasonable to presume that the later improvements were such an advance that they suggested supernatural origin; _e.g._, the sword of Siegfried, the name of which was Balmung or Gram (literally “grief”). The sword was reputed to be made by Wieland Smith, the Vulcan of the Scandinavians. To test the blade he tried it on Amilias, a brother smith, cleaving him through helm and armour down to the waist, but the cut was so fine that Amilias was not aware that he was wounded until he attempted to move, when he fell in two pieces. Arthur’s sword Excalibur (liberated from the stone) is a later development, as the magical property was in the sheath, which rendered the wearer immune from injury. Arthur’s undoing was the result of losing the sheath, though he retained the sword. _Invulnerability_ Associated with this is invulnerability, variously bestowed or acquired. In the tradition of Achilles, he was immersed in the river Styx by his mother Thetis, but the immersion did not extend to his heel, in which he received his mortal wound from the arrow of Paris. Jason was rendered invulnerable in his battle with the giants that sprang from the sowing of the Cadmean teeth by being anointed by Medæa with the Promethean unguent. Siegfried, the horny, made himself similarly proof from injury by bathing in the dragon’s blood, but one spot on his back, where a linden leaf had stuck, escaped. Through this only vulnerable spot he met his death, being killed by Hagan the Dane while drinking in a pool. This probably is a poetic allusion to early employment of defensive armour, in which the back, as compared to the front, would be unprotected. _Belief in Numbers_ Certain numbers have at all times been invested with mystic significance, _e.g._, “Three” the “perfect” number, expressive of Beginning, Middle and End; also symbol of Deity. An earlier term of Trinity is Triad, and almost every mythology has a three-fold deity.