'The Saga of Grettir the Strong' is one of the Icelanders' sagas. It details the life of Grettir Ásmundarson, a bellicose Icelandic outlaw. The first part of the story primarily focuses on how Grettir's viking great-grandfather Onundur Tree-foot escaped Norway to settle in Iceland after fighting in the Battle of Hafrsfjord against the first king of Norway Harald Fairhair.