The sunstone is a type of mineral attested in several 13th–14th-century written sources in Iceland, one of which describes its use to locate the Sun in a completely overcast sky. Sunstones are also mentioned in the inventories of several churches and one monastery in 14th–15th-century Iceland and Germany.

Rauðúlfs þáttr is a short allegorical story preserved in Iceland in a number of medieval manuscripts. The author is unknown but was apparently a 12th–13th century ecclesiastical person. The story is about Saint Olav's visit to a wise man named Rauðúlfr, their entertainment in the evening, the staying overnight in a round, rotating and richly decorated house and a vision the king had in his dream that night. The story is sometimes incorporated in the Separate Saga of St. Olaf.