Prose
The word "prose" first appears in English in the 14th century. It is derived from the Old French "prose", which in turn originates in the Latin expression "prosa oratio" (literally, straightforward or direct speech).
Æsir–Vanir War
In the "Prose Edda" book "Skáldskaparmál" (chapter 57), the god Bragi explains the origin of poetry. Bragi says that it originated in the Æsir–Vanir War, when during the peace conference the Æsir and the Vanir formed a truce by all spitting into a vat. When they left, the gods decided that it should not be poured out, but rather kept as a symbol of their peace, and so from the contents made a man, Kvasir. Kvasir is later murdered, and from his blood is made the Mead of Poetry.