The Sword of Light or Claidheamh Soluis (Old Irish; modern Irish: Claíomh Solais [ˌklˠiːw ˈsˠɔlˠəʃ]) is a trope object that appears in a number of Irish and Scottish Gaelic folktales. The "Quest for sword of light" formula is catalogued as motif H1337. The sword has been regarded as a legacy to the god-slaying weapons of Irish mythology by certain scholars, such as T. F. O'Rahilly, the analogues being the primeval Celtic deity's lightning-weapon, Lugh's sling that felled Balor, the hero Cúchulainn's supernatural spear Gae bulga and his shining sword .