https://en.wikipedia.org/wiki/Sigurd_Snake-in-the-Eye

About Sigurd "Snake-in-the-eye" Ragnarsen
Alt Birth Dates: c. 786, c. 776, c. 782

Alt Death Dates: c. 873, c. 799, 866, 803

Sigurd Snake-in-the-Eye, Jarl of Zealand, Halland, Scania, Denmark & Viken

Sigurd Snake-in-the-eye was one of the sons of Ragnar Lodbrok and Kraka, but what set him apart from the others was that he was born with the image of the ouroborous, a snake or dragon biting its own tail, encircling the pupil of his left eye.

Ragnarssona þáttr informs that when his father died, he inherited Zealand, Scania, Halland, the Danish islands, and Viken. He married Blaeja, the daughter of king Aelle II of Northumbria and they had the children Harthacanute and Aslaug .

Historians have suggested that Harthacnut was a grandson of Sigurd rather than a son; both claims are impossible to verify.

Sigurd's daughter Aslaug married Helgi the Sharp of the Dagling dynasty. They had the son Sigurd Hart, who married Ingeborg, the daughter of the Jutish chieftain Harald Klak. Sigurd Hart and Ingeborg had the children Guttorm and Ragnhild. When his uncle king Fróði of Ringerike died, Sigurd Hart went to Norway to succeed him as king.

Ragnarssona þáttr and Heimskringla relate that a berserker from Hadeland named Haki killed Sigurd Hart, but lost a hand in the fight. Then Haki went to Sigurd Hart's residence at Stein and took Sigurd's children Ragnhild and Guttorm. Haki returned with the children and all the loot to Hadeland. Before Haki recuperated from his wounds and could marry the 15 year old Ragnhild, she was captured a second time, by Halfdan the Black. Halfdan and Ragnhild were the parents of Harald Fairhair.

According to legend Sigurd’s had 2 children, but genealogists refer to 7 children.

The attacks of the Great Heathen Army began in 863