Complex sentence: According to South "there is now general agreement that Halfdan is identical with Albann", where Halfdan is Halfdan Ragnarsson, a commander of the Great Heathen Army and (according to the Norse sagas) son of the legendary Viking Ragnar Lodbrok.
Split into simpler sentences: According to South "there is now general agreement that Halfdan (Ragnarson) is identical with Albann". Halfdan Ragnarson was a commander of the Great Heathen Army and (according to the Norse sagas) son of the legendary Viking Ragnar Lodbrok.