Narrative fiction is any story (or book) that tells a fictional tale, or one which is not true.
An official letter on a papyrus of the 3rd century BCE. Papyrus is first known to have been used in ancient Egypt (at least as far back as the First Dynasty), as the Cyperus papyrus plant was a wetland sedge that was once abundant in the Nile Delta of Egypt. It was also used throughout the Mediterranean region and in Kingdom of Kush.
Actually, Toby Fox tweeted that in a Japanese version, Papyrus would call Sans aniki, which is a reverent way to address an older brother. And Papyrus' username hints he may have been born in 95, so he's likely between 15 and 24 during the story, which takes place in 201X.