The relation of the Saga to authentic history had always been close. The first attempt to give shape, in writing, to the traditions of the heroic age was made by Ari Thorgilsson (_ob._ 1148), especially in his _Landnámabók_, a history exact and positive, a record in detail of all the first settlers of the island, with notes of the substance of the popular stories by which their fame was transmitted. This exact history, this positive work, precedes the freer and more imaginative stories, and supplies some of them with a good deal of their matter, which they work up in their own way. The fashion of writing, the example of a written form of narrative, was set by Ari; though the example was not followed closely nor in all points by the writers of the Sagas: his form is too strict for them. It was too strict for his greatest successor in historical writing in Iceland. Snorri Sturluson is the author of _Lives of the Kings of Norway_, apparently founded upon Ari's _Book of Kings_, which has been lost as an independent work. Snorri's _Lives_ themselves are extant in a shape very far from authentic; one has to choose between the abridged and inconvenient shape of _Heimskringla_, in which Snorri's work appears to have been cut down and trimmed, and the looser form presented by such compilations as the longer Saga of Olaf Tryggvason, where more of Snorri appears to have been retained than in _Heimskringla_, though it has to be extricated from all sorts of irrelevant additions and interpolations. But whatever problems may still remain unsolved, it is certain enough that Snorri worked on his historical material with no intention of keeping to the positive lines of Ari, and with the fullest intention of giving to his history of Norway all the imaginative force of which he was capable. This was considerable, as is proved by the stories of the gods in his _Edda_; and in the histories of Olaf Tryggvason and of Saint Olaf, kings of Norway, he has given companions to the very noblest of the Sagas dealing with the Icelandic chiefs. Between the more scientific work of Ari and the more imaginative work of Snorri comes, half-way, the _Life of King Sverre_ (_ob._ 1202), written at the king's own dictation by the Abbot Karl of Thingeyri. Ari collected the historical materials, both for Iceland and Norway, and put them together in the extant _Landnámabók_ and the lost _Kings' Lives_. Snorri Sturluson treated the _Kings' Lives_ in the spirit of the greater Icelandic Sagas; his _Lives_ belong to heroic literature, if there is any meaning in that name. The _Life of Sverre_ is not so glorious as the _Life_ of either Olaf. Abbot Karl had not the same interests or the same genius as Snorri, and his range was determined, in most of the work, by the king himself. King Sverre, though he could quote poetry to good effect when he liked, was mainly practical in his ideas.