Under God's Rock by Tim Urban

"Under God's Rock" is set in 11th-century Normandy. Crippled in his youth, a blasphemous monk named Wido, unearths a relic the Bible says does not exist - and the Catholic Church never wants to be found. By a twist of fate he crosses paths with the Viking, Styrkar, and both will come to have their lives changed by the boulder known as God's Rock.