Composed as a textbook on the traditional Old Norse skaldic poetry, Snorri Sturluson's Edda is the most important source of our knowledge of pre-Christian Scandinavian mythology. The opening shows the story of the slaying of the god Baldr, an act which leads to the end of the old world, Ragnarök. The manuscript also contains the only known copy of a very important treatise on the Icelandic language dating from the 12th century. The codex, written c.1350, is named after the renowned Danish antiquarian and founder of runology Ole Worm, who in 1628 acquired it as a gift from Iceland. Arni Magnusson acquired it from his grandson in 1706.