AH HAH! this is what I read.
"The mystery of Sheogorath and his realm are revealed in the tome called Shivering Isles. The realm of Sheogorath was previously known as Madhouse, but in the recent survived tome, we know that the realm of madness is called Shivering Isles by Sheogorath himself. The tome tells the story of a young hero who was hired by Sheogorath to stop the Greymarch, an event that occurs in the end of an Era. According to Yngvar the Wanderer in his book "The Predecessors", the Greymarch occurs every 1000 years, thus we may assume that an Era in Shivering Isles is 1000 years."
quoted from http://www.imperial-library.info/book_daedra/index1.shtml#sheogorath It never refers to them as "the champion of cyrodill" just as "young hero" so that leaves it open for us to decide i suppose
yay for role-playing games!