During the days of Valdemar and the great Birger Norway also reached its greatest territorial extent. After a century of factional warfare, the nation settled down to comparative peace. All the Norwegian colonies except those in Ireland, were definitely made subject to the Norwegian crown: these were the Isle of Man, the Hebrides, the Orkneys, the Shetlands, the Faroes, Iceland, and Greenland. In every field of national life there was vigor and enterprise. And on the throne sat a strong, wise, and learned monarch, Hakon IV, the ruler with the “great king-thought.” The real greatness of the thirteenth century in the North lies, however, in the literary achievements of the age. It is not known when the Old Norse poets first began to exercise their craft, but the earliest poems that have come down to us date from the ninth century. For two hundred years the literary production was in the form of alliterative verse; but after 1050 there came a time when scaldic poetry did not seem to thrive. This does not mean that the interest in literature died out; it merely took a new form: the age of poetry was followed by an age of prose. With the Christian faith came the Latin alphabet and writing materials, and there was no longer any need to memorize verse. The new form was the saga, which began to appear in the twelfth century and received many notable additions in the thirteenth. The literary movement on the continent, therefore, had its counterpart in the North; only here the writings took the form of prose, while there literature was chiefly in verse. These two currents came into contact in the first half of the thirteenth century, when the men and women of the North began to take an interest in the Arthurian romances and other tales that had found their way into Norway. In this new form of Norwegian literature there could not be much originality; still its appearance testifies to a widening of the intellectual horizon. In addition to sagas and romances the period was also productive of written laws, homilies, legends, Biblical narratives, histories, and various other forms of literature. It is to be noted that virtually everything was written in the idiom of the common people. Latin was used to some extent in the North in the later middle ages, but it never came into such general use there as in other parts of Europe. In the thirteenth century it had almost passed out of use as a literary language.