Thorulf is known only from one source. According to the late 11th-century
Saxon writer
Adam of Bremen, he was appointed as bishop of
Blascona in Orkney by
Adalbert,
Archbishop of Hamburg. In the mid-11th century, the Archbishop of Hamburg's jurisdiction extended over Scandinavia. Historians identify
Blascona with
Birsay (
Old Norse:
Birgisherað),
Blascona a Latinisation perhaps derived from an older form. Adam leaves no personal details about Thorulf, but supplies some information about the Orkney see, stating that the: ...Orkney Islands, although they had previously been ruled by English and Scottish bishops, our primate [Adalbert] on the pope's order consecrated Thorulf bishop for the city of Birsay [
in civitatem Blasconam], and he was to have cure of all. The date was approximately 1050, though could have been at any point between 1043 and 1072, the episcopate of Adalbert. The date 1050 is suggested as this was around the time that Earl
Thorfinn Sigurdsson, ruler of Orkney, visited Rome. ==Thorulf and Thorfinn==