Thorstein the Red or Thorstein Olafsson was a viking

Viking

The term Viking is customarily used to refer to the Norse explorers, warriors, merchants, and pirates who raided, traded, explored and settled in wide areas of Europe, Asia and the North Atlantic islands from the late 8th to the mid-11th century.These Norsemen used their famed longships to...

 chieftain who flourished in late ninth-century Scotland

Scotland

Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

. He was born around 850 AD and was the son of Olaf the White

Olaf the White

Olaf the White was a viking sea-king who lived in the latter half of the 9th century.Olaf was born around 840, possibly in Ireland. His father was the Hiberno-Norse warlord Ingjald Helgasson...

, King of Dublin, and Aud the Deep-minded

Aud the Deep-Minded

Aud the Deep-Minded was an earlier settler in Iceland.-Biography:...

, who was the daughter of Ketil Flatnose

Ketil Flatnose

Ketill Bjǫrnsson, nicknamed Flatnose , was a Norwegian hersir of the 9th century.-Biography:Ketill Bjǫrnsson was the son of Bjorn Grimmson. He was from Romsdal , a valley in the county of Møre og Romsdal, between Nordmøre and Sunnmøre...

. After the death of Olaf, Aud and Thorstein went to live in the Hebrides

Hebrides

The Hebrides comprise a widespread and diverse archipelago off the west coast of Scotland. There are two main groups: the Inner and Outer Hebrides. These islands have a long history of occupation dating back to the Mesolithic and the culture of the residents has been affected by the successive...

, then under Ketil's rule.
Thorstein eventually became a warlord and allied with the Jarl of Orkney, Sigurd Eysteinsson

Sigurd Eysteinsson

Sigurd Eysteinsson was the second Viking Earl of Orkney, who succeeded his brother Rognvald Eysteinsson. He was a leader in the Viking conquest of what is now northern Scotland. Bizarrely, he was killed by the severed head of one his enemies, Máel Brigte, who may have been mórmaer of Moray...

. Together Thorstein and Sigurd waged a series of campaigns in Caithness

Caithness

Caithness is a registration county, lieutenancy area and historic local government area of Scotland. The name was used also for the earldom of Caithness and the Caithness constituency of the Parliament of the United Kingdom . Boundaries are not identical in all contexts, but the Caithness area is...

, Sutherland

Sutherland

Sutherland is a registration county, lieutenancy area and historic administrative county of Scotland. It is now within the Highland local government area. In Gaelic the area is referred to according to its traditional areas: Dùthaich 'IcAoidh , Asainte , and Cataibh...

, Ross

Ross

Ross is a region of Scotland and a former mormaerdom, earldom, sheriffdom and county. The name Ross allegedly derives from a Gaelic word meaning a headland - perhaps a reference to the Black Isle. The Norse word for Orkney - Hrossay meaning horse island - is another possible origin. The area...

, Moray

Moray

Moray is one of the 32 council areas of Scotland. It lies in the north-east of the country, with coastline on the Moray Firth, and borders the council areas of Aberdeenshire and Highland.- History :...

, and a number of other regions, eventually receiving tribute from half of Scotland

Scotland

Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

. However, the Scottish chieftains plotted against Thorstein, and he was killed; the exact nature of his death is unknown but it probably took place around 880 or 890. After Thorstein's death Aud left Caithness, sojourning for a while in Orkney before settling with other members of her clan in Iceland

Iceland

Iceland , 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...

.

Thorstein married Thurid, the daughter of Eyvind the Easterner. Thorstein and Thurid had a son, Olaf Feilan

Olaf Feilan

Olaf Feilan was an Icelandic gothi of the Settlement period. He was the son of Thorstein the Red, jarl of Caithness, and his wife Thurid Eyvindsdottir. After the death of his father Olaf accompanied his grandmother Aud the Deep-minded to Iceland, and settled with her at Hvamm in the Laxardal region...

, and a number of daughters, including Groa

Gróa

In Norse mythology, Gróa is a völva and practitioner of seiðr, the wife of Aurvandil the Bold.-Prose Edda:Gróa appears in the Prose Edda book Skáldskaparmál, in the context of Thor's battle with the jötunn Hrungnir...

, Thorgerd, Olof, Osk, Thorhild, and Vigdis. A woman named Unn, wife of Thorolf Mostur-beard, claimed to be the daughter of Thorstein, but this claim was viewed by other Icelanders with skepticism.