Ingjald Helgasson was a Hiberno-Norse chieftain of the ninth century AD. According to the Landnamabok

Landnámabók

Landnámabók , often shortened to Landnáma, is a medieval Icelandic written work describing in considerable detail the settlement of Iceland by the Norse in the 9th and 10th centuries AD.-Landnáma:...

 he was the son of Helgi, the son of Olaf, the son of Gudrod, the son of Halfdan Hvitbeinn

Halfdan Hvitbeinn

Halfdan Whiteshanks was a mythical petty king in Norway, described in the Ynglinga saga. The following description is based on the account in Ynglinga saga, written in the 1220s by Snorri Sturluson. The historicity of the kings described in that saga is generally not accepted by modern...

; he was thus distantly related to the Yngling

Yngling

The Ynglings were the oldest known Scandinavian dynasty. It can refer to the clans of the Scylfings , the semi-legendary royal Swedish clan during the Age of Migrations, with kings such as Eadgils, Onela and Ohthere...

 kings of Vestfold

Vestfold

is a county in Norway, bordering Buskerud and Telemark. The county administration is in Tønsberg.Vestfold is located west of the Oslofjord, as the name indicates. It includes many smaller, but well-known towns in Norway, such as Larvik, Sandefjord, Tønsberg and Horten. The river Numedalslågen runs...

 and later Norway

Norway

Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...

. According to Eyrbyggja saga

Eyrbyggja saga

Eyrbyggja saga is one of the Icelanders' sagas. The name means the saga of the inhabitants of Eyrr, which is a farm on Snæfellsnes on Iceland. The name is slightly misleading as it deals also with the clans of Þórsnes and Alptafjörðr. The most central character is Snorri Þorgrímsson or Snorri goði...

, Ingjald's mother was Thora, the daughter of Sigurd Snake-in-the-Eye who was a son of Ragnar Lodbrok

Ragnar Lodbrok

Ragnar Lodbrok was a Norse legendary hero from the Viking Age who was thoroughly reshaped in Old Norse poetry and legendary sagas.-Life as recorded in the sagas:...

.

Ingjald had at least one son, 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...

, who became King of Dublin.