Gissur Thorvaldsson was a medieval
IcelandIceland , described as the Republic of Iceland, is a Nordic and European island country in the North Atlantic Ocean, on the Mid-Atlantic Ridge. Iceland also refers to the main island of the country, which contains almost all the population and almost all the land area. The country has a population...
ic chieftain or
goði of the
HaukdælirThe Haukdælir were one of the family clans who controlled medieval Iceland during the period of the Icelandic Commonwealth. Their name is derived from Haukadalur . The Haukdælir traced their lineage to Ketilbjörn Ketilsson, who settled on land in Grímsnes and received a Goðorð in Árnesþing...
family clan, and great-grandson of
Jón LoftssonJón Loftsson was chieftain at Oddi in the county of Rangá in the south part of Iceland, and of the Oddaverjar family clan. He was one of the most popular chieftains and politician of his age in the country. He participated in the so-called Staðarmál, in 1179, against the Roman-Catholic Church and...
.
Gissur played a major role in the period of civil war which is now known as
Sturlungaöld, or the
Age of the SturlungsThe Age of the Sturlungs or the Sturlung Era was a 42-44 year period of internal strife in mid 13th century Iceland. It may also have been the bloodiest and most violent period in Icelandic history...
: he fought alongside Kolbeinn the Young against the forces of
Sturla SighvatssonSturla Sighvatsson was an Icelandic chieftain or goði of the Sturlungar family clan who played an active role in the armed conflicts in Iceland during the Age of the Sturlungs ....
of the Sturlungar clan in the
Battle of ÖrlygsstaðirThe Battle of Örlygsstaðir was a historic battle fought by the Sturlungar against Ásbirningar and the Haukdælir clans in northern Iceland. The battle was part of the civil war that was taking place in Iceland at the time between various powerful clans , and was the largest battle in the history of...
in 1238 and led the force of men who murdered saga-writer
Snorri SturlusonSnorri Sturluson was an Icelandic historian, poet, and politician. He was twice elected lawspeaker at the Icelandic parliament, the Althing...
in 1241, at the behest of Haakon IV, King of Norway. In 1258, he was made Earl of Iceland for his loyal service to the king. He held this title until his death.
Gissur worked actively to promote the Old Covenant , an agreement which brought
IcelandIceland , described as the Republic of Iceland, is a Nordic and European island country in the North Atlantic Ocean, on the Mid-Atlantic Ridge. Iceland also refers to the main island of the country, which contains almost all the population and almost all the land area. The country has a population...
under the sovereignty of the Norwegian crown in 1264. The covenant is hence sometimes known as Gissur's Covenant, or
Gissurarsáttmáli.