Caladbolg ("hard cleft", also spelled Caladcholg, "hard blade") is the sword of Fergus mac Róich from the Ulster Cycle of Irish mythology. Fergus calls his sword by that name in Táin Bó Cúailnge. Ailill mac Máta had stolen Fergus's sword when he caught him in flagrante with Medb. Fergus carved a dummy wooden sword to disguise the fact he was unarmed. Ailill returns the sword to him before the final battle, and Fergus speaks a poem over it, calling it Caladcholc in one version, and Caladbolg in another. It is said to have been "the sword of Leite from the elf-mounds. When one wished to strike with it, it was as big as a rainbow in the air." Prevented from using it against Conchobar mac Nessa, Fergus instead cuts off the tops of three hills.