During the 11th and 12th centuries, Iceland’s political landscape changed as power became centralized in the hands of a few dominant families, eroding the independence of local farmers and chieftains. This period, from around 1200 to 1262, is known as the Age of the Sturlungs, named after the powerful Sturlung family, including Snorri Sturluson and his nephew Sturla Sighvatsson. The Sturlung clan, along with rival families, engaged in violent power struggles that destabilized the island, which was mostly populated by farmers uninterested in these conflicts.
In 1220, Snorri Sturluson became a vassal of the Norwegian king, Haakon IV, increasing Norway's influence in Iceland. Over time, as internal conflicts persisted, Icelandic chieftains eventually accepted Norwegian sovereignty, signing the Old Covenant (Gamli sáttmáli) in 1262–1264, which formalized Iceland’s union with Norway and marked the end of the Icelandic Commonwealth.
This era also saw significant disputes over the control of church wealth, known as the staðamál. These conflicts culminated in a transfer of power and wealth from secular aristocrats to the Church, which became more independent from secular authority.