The Akkadians had no word for poem or novel, and they wrote in a way that
destroyed whatever rhyme there might have been, so we don't really know what
was has to be categorized as novel or poetry, and translators have arbitrarily
opted for one or another form.
The dates of ancient works are obviously wildly approximate.
See Steve Moore: "The Novel" for synopses of these works.
(For the time being only the novels)
"Inanna's Descent" (?) in Sumerian
"Eridu Genesis" (16## BC) in Sumerian
"Enmerkar and the Lord of Aratta" (?) in Sumerian
Ipiq-Aya: "Atrahasis/ The Flood" (17## BC) in Akkadian
"Gilgamesh" (15## BC) ++ in Akkadian
"Enuma Elish/ Epic of Creation" (12## BC) in Akkadian
Kabti-ilani-Marudk: "Erra and Ishum" (7## BC)