Edda

The term Edda (Old Norse Edda, plural Eddur) applies to the Old Norse Poetic Edda and Prose Edda, both of which were written down in Iceland during the 13th century in Icelandic, although they contain material from earlier traditional sources, reaching into the Viking Age. The books are the main sources of medieval skaldic tradition in Iceland and Norse mythology.

Read more about Edda:  Etymology, The Poetic Edda, The Prose Edda