Kinsman Redeemer

A promise pact written on parchment was made between the Englishman Lord Harold of Rockhaven Castle and Kormac the Dane. But the parchment was stolen and altered. When King Svein Forkbeard arrives at Rockhaven in the spring of 1013 with that parchment he claims to be the recipient of the promises.
Wiley,13, alias Son of Nobody, is recognized by two Danish strangers. The parchment disappears again and Wiley flees for his life. Aided by an alchemist with Greek Fire, Thoren the Viking, a dwarf named Toadskin plus Forkbeard's son Knute, 17, Wiley learns his history and gains insight into God's foreknowledge.