Heimskringla is the best known of the old Norse kings' sagas. It was written in Old Norse in Iceland by the poet and historian Snorri Sturluson (1179 - 1242) ca. 1230. The name Heimskringla was first used in the 17th century, derived from the first two words of one of the manuscripts (kringla heimsins - the circle of the world).
Heimskringla is a collection of tales about the Norwegian kings, beginning with the legendary Swedish dynasty of the Ynglingas, followed by accounts of historical Norwegian rulers from Harald Fairhair of the 9th century up to the death of the pretender Eystein Meyla in 1177. The exact sources of his work are disputed, but included earlier kings' sagas, such as Morkinskinna, Fagrskinna and the twelfth century Norwegian synoptic histories and oral traditions, notably many skaldic poems. Snorri had himself visited Norway and Sweden. For events of the mid 12th century, Snorri explicitly names the now lost work Hryggjarstykki as his source. The composition of the sagas is Snorri's.