After divorcing his first wife, the shield-maiden Lagertha, Ragnar wanted to make Thora his wife. He went to the bower, wearing breeches that he had treated with tar and sand to protect his legs from the serpent's poison.
Following his divorce from Lagertha, Ragnar desired to marry Thora. To protect himself from the venomous bite of a serpent, he wore trousers coated in tar and sand.