Yes, Viking Saga is a modern fiction, written by me. The description says Viking Saga is a novel written in 2009 by Mark Coakley, the "translator's note" is dated 2010, and there are many other internal clues ... The "false document" is a long-standing fictional device that was used in the very first novel, Robinson Crusoe, which Defoe presented as the diary of a shipwrecked sailor ... Wikipedia has a good article about false documents --
http://en.wikipedia.org/wiki/False_document ... It's not done to trick readers, but to make it easier to willingly suspend disbelief ... Should I make it more obvious?
PS -- The two saga's mentioned by Ea happen to be my two favourites, and used as research for Viking Saga. The book uses a lot of saga conventions, while trying to jazz it up a bit for modern tastes.