SNORRI STURLUSON (1179–1241) is Iceland's greatest historian. His writings include the Prose Edda and the Heimskringla, which along with the Poetic Edda are the major primary sources for Germanic mythology and religion. Snorri was sent at a young age to a settlement in southern Iceland called Oddi to be fostered by Jón Loptsson, grandson of Sæmund Sigfússon and of Magnus III of Norway. Jón Loptsson was the most powerful chieftain in Iceland at the time, and his farm was a center of learning without equal. Snorri received the best education possible; his power and stature increased, and he was elected law speaker in 1215. After one term, ending in 1218, he journeyed to Norway to visit its rulers, the regent Earl Skúli and the young King Hákon. For several years Snorri traveled widely throughout Norway and Sweden. He thwarted a scheme to force...