Career
After studying in Herford in Germany, he was made bishop of Iceland in 1056 by Athelbjart, archbishop of Bremen. He built up a see in his family homestead in Skálholt and founded a school. One of his students was Jón Ögmundarson, who later became the first bishop in Hólar.
Ísleifur served as bishop for 24 years, right until his death.