This paper aims to give an account of, and to discuss the view-points and theories of different researchers on the christianization of Sweden, especially the province of Öland, during the early middle ages. Its purpose is to investigate how, and in what sense, their positions can be said to correspond to what we may know of the historical “facts”. This will be possible by comparing different points of view with a study of the development in a single parish. An overall difficulty however, is the nature of the sources relating to the time in question, they are scarce or even non-existent. Part I of the paper consists of an outline of the field of research and the different theories put forward on the subject. The account is thematic, since there are several different problematic areas linked to the subject of Sweden’s christianization that each needs separate attention – though they all are, of course, interrelated. The account continues in part II, but with the focus on the iron-age society of Öland, its social, administrative and economic structure, and the major societal change that occurred roughly around AD 1000 – a change wherein the christianization was an important aspect. Part III consists of a micro-study of Föra parish in the north of Öland through the years 400-1300 approximately. Finally, part IV gives a summary and the results of the study in part III are compared to relevant theories and view-points discussed in parts I and II. The conclusions that can be drawn from the comparison are A) Some of the view-points can be seen as tentatively confirmed (and some others as refuted), and B) An extended comparative approach could serve as an instrument for shaping theoretical models with a higher level of generality, since the comparison also shows that the results of historical research often is governed by a theoretical bias, even when empirical material is incomplete, corroborated or contradictory to the results.