Complex sentence: The text says that many men fled from Norway when Harald Hårfagre was king there, but it also says that the isles were settled before that (possibly for hundreds of years, although most historians do not think so).
Split into simpler sentences: The text says that many men fled from Norway when Harald Hårfagre was king there. But it also says that the isles were settled before that (possibly for hundreds of years, although most historians do not think so).