The Edda are the sagas of medieval Iceland, as they are usually called, a series of texts describing various aspects of the society from their laws to their religious beliefs.
Some texts are in prose, while some are poetic.
The sagas of medieval Iceland are some of the West's most fascinating literature, arising from one of the West's most fascinating civilizatons. Iceland was settled by the Norse in the late 9th century, and has been inhabited since then. It's cultural distinctions include not only that early exploration and settlement but a democratic parliament as well. Many of the sagas apparently date to this period, and possibly even prior to settlement, but were written down only from around the 13th century. This poetry and its recitation are inherently oral traditions.