The scarcity of written source material is a constant problem for scholars of the Christianisation of Sweden. In order to overcome this problem, at least to some extent, comparisons with Christianisation in other geographical areas can be useful. In this way similarities and differences between the areas can be identified. It may also be possible to illuminate the meagre and at times confusing source material, and to find indications of what questions could be asked. The purpose of this chapter is to investigate the role played by secular rulers in the conversion of Sweden. Background information has been derived from the better documented conversions of Anglo-Saxon England, Frisia and Saxony. The emphasis will be placed on the role of secular rulers in the early stages of conversion, that is England, in the seventh century, Frisia and Saxony during the seventh and eighth centuries and Sweden between the ninth and early twelfth centuries. Despite the obvious differences in time and geography, it is evident that important parallels can be found.

From the study of Anglo-Saxon England, Frisia and Saxony, it clearly emerged that a converted ruler was necessary, although not sufficient, for widespread conversion. Missionaries who worked without the support of a Christian ruler could gain a few converts. They were however not able to turn a non-Christian society into a Christian one. Evidence suggests that rulers aided conversion by certain means, many of which were common for all geographical areas. These will now be discussed in order to illuminate how secular rulers in Sweden may have helped the spread of Christianity. The following issues will be discussed: the rulers’ use of bonds of loyalty in society, secular legislation in support of Christianity, together with royal protection and material aid given to missionaries and converts.

Christianity in Anglo-Saxon England seems to have spread between the various kingdoms via the power of the overkings. It is unlikely that underkings were forced to accept Christianity, and there is no evidence that armies were actively employed in the name of conversion. Instead, overkings made use of the strong bonds of loyalty that tied the underkings to their overlordship. Christianity was then spread to the aristocracy and further down in society via the pre-feudal hierarchical structure within the Anglo-Saxon kingdoms. The way in which an overking influenced conversion can be demonstrated by the example of King Ethelbert of Kent.