In the historiography of the Swedish language, the New Testament translation of 1526 (NT1526) is often used to represent the beginning of the early modern language period. It is, no doubt, the single most important text of the new Early Modern Swedish, a variety which is so close to present-day Swedish that it is still legible for modern readers without too much effort. At the same time, Mediaeval Swedish (ʻOld Swedish’) generally requires of its reader proficiency in that specific language. The transition between these two varieties of Swedish can be described as the most dramatic change in the history of the language, as the entire system was affected, from lexis to syntax, morphology, and phonology. There are thus good reasons to speak about two different eras in language history.

The traditional border is furthermore stressed by the general historical changes in this period which includes the breakup of the Nordic political union, the establishment of a new regime with an efficient administration, and not least the introduction of the Lutheran Reformation programme. However, among historians there are several different alternative models for understanding how the centuries before and after 1500 relate to each other. Some speak of ʻthe long Middle Ages’, for instance, emphasizing the fact that many cultural features did not change at the beginning of the 16th century but continued to be important in the centuries to come. Others, particularly among specialists on the Reformation, recognize a period of its own, comprising parts of the 14th to the 17th centuries.