The Viking adventurer Rollo (ca. 860-ca. 932) founded the line of the dukes of Normandy. He established Viking control of the lands at the mouth of the Seine River and thus began what became the most powerful French dukedom.
Probably born in Norway, Rollo, or Rolf, was the son of Rögnvald, Earl of Möre. Chronicle sources, which are not always reliable, note that he was exiled from Norway because of lawlessness, probably about 900. Rollo became a Viking raider and for a time was successful. He went to Scotland, where he married a Christian woman by whom he had a daughter; and possibly from this marriage his son, later known as William Longsword, his successor in Normandy, also issued. Rollo then may have gone to Ireland, but with the waning of Norse power in Ireland he probably followed his compatriots who traveled to France, where raiding parties could find richer opportunities for looting.
Rollo probably arrived in Gaul between 905 and 911. During these years he became famous, and stories about him circulated in his homeland: "Rolf [Rollo] was a great Viking: he was so big that no steed could bear him, so that he was called Rolf 'the Ganger."' Rollo's name figured prominently in the treaty between King Charles the Simple of France and the Seine Vikings in 911. By that famous agreement, the Vikings received control of the territory at the mouth of the Seine in return for certain services to the King. Rollo himself was granted Upper Normandy (the territory between the Epte River and the sea), and he was converted to Christianity and baptized by the archbishop of Rouen. Rouen was the capital of the ecclesiastical province of Normandy, which Rollo's successors later added to their initial territory.
In 924 Rollo added the lands of Bessin and Maine to his holdings, and after his death his successor, William Longsword, completed the construction of the duchy by adding the lands of the Cotentin and the Avranchin to Rollo's acquisitions. Rollo's conversion to Christianity, however, and his gift of land from the king of France should not be misinterpreted. Very likely Rollo's Christianity was of a very limited character, and his supposed loyalty to the king of France could not be counted upon. Early Norman domination of the lower Seine Valley contributed to the disintegration of ecclesiastical and economic institutions in that area, but Rollo's able successors shaped a strong and flourishing duchy in the territory that their vigorous and bloodthirsty ancestor had conquered. Rollo was the great-great-great-grandfather of William the Conqueror (William I of England).
In 927 Rollo abdicated in favor of William Longsword.
There is no biography of Rollo in English. A good recent survey of the Normans is David C. Douglas, The Norman Achievement, 1050-1100 (1969), recommended as an introduction for the general reader. See also Richard W. A. Onslow, The Dukes of Normandy and Their Origin (1947).