Final answer:
The existence of a sixteenth-century monastery on a remote Swedish island is surprising because Viking raids often targeted undefended religious sites and knowledge of remote locations was not widespread.
Step-by-step explanation:
The discovery of a sixteenth-century monastery on a remote island off the Swedish coast would be surprising for several reasons based on the provided passage information. Monasteries were often established in locations that supported a life of asceticism, which remote islands could potentially provide. However, the historical context suggests that Viking raids were common and they specifically targeted churches and monasteries for their lack of defenses and wealth. This would make the establishment of a monastery on a remote island, which may have been exposed to Viking raids less likely. Moreover, the passage highlights that the Norse had knowledge of lands farther west which survived in sagas, implying that the spread of this information was limited and not widespread across Europe. This would also make it less likely for monks to have knowledge of such remote islands to establish a monastery in the sixteenth century.