Complex sentence: The powerful Icelandic "goði" chieftain Gissur Þorvaldsson had returned from Norway with the Norwegian King's favour, and had settled in Flugumýri in Skagafjörður, an ancient homestead in Blönduhlíð where the chieftans of the Ásbirningar clan lived.
Split into simpler sentences: The powerful Icelandic "goði" chieftain Gissur Þorvaldsson had returned from Norway with the Norwegian King's favour, and had settled in Flugumýri in Skagafjörður. Flugumýri is an ancient manor in Blönduhlíð, where the chieftans of the Ásbirningar clan lived.