The Vikings worshiped mainly by sacrifice. That meant giving up something of value, including jewelry, weapons, ships, animals, and even people. The book describes a Norse universe steeped in mythology. There are gods and goddesses such as Odin, Thor, Freya, and the evil Loki, and there are descriptions of the great halls where they reside. By A.D. 1050, most Scandinavian people had converted to Christianity.