The three Norns in Norse mythology, known as Urd, Verdandi, and Skuld, are goddesses who govern fate. They weave the threads of life and determine the destinies of gods and mortals alike. Each Norn has a specific role: Urd represents the past, Verdandi embodies the present, and Skuld signifies the future. Their interplay emphasizes the Norse understanding of time and destiny's influence on existence.