In order to understand how world religions such as Christianity spread, we need to investigate routes of religious exchange. This paper examines Scandinavian exposure to Christianity in the Viking Age from a maritime and theological perspective. It does so by combining literary, graphic, and material evidence with a field study of ancient boatbuilding, which is uniquely preserved in Russia. It investigates how Scandinavians in large numbers reached the Christian metropolis Constantinople by adapting their boatbuilding skills to Slavic nautical technology. An analysis of De Administrando Imperio proves that Scandinavians used and outfitted the Slavic expanded logboat in the text named σκαφίδιον (“skafidion”) along Put’ iz varjag v Greki from the Novgorod Region. It argues that this particular Slavic technology was the precondition for naval expeditions to Constantinople, and it offers a new explanation as to why Slavs over time used the term Rus as a signifier to identify themselves. The paper shows that this is cooperated and elaborated by the field study of the Russian expanded logboat ‘ботник’ (botnik). The paper argues that this study substantiates the claim in The Russian Primary Chronicle also known as Povest’ vremennykh let, that several thousand Scandinavians and Slavs reached Constantinople during their naval expeditions in year 860, 907, and 941, and the information that some of them were baptized in Constantinople, during these years. It is argued that the first major conversion of the Scandinavian elite took place abroad. Because of ботник, Scandinavians together with Slavs were exposed to the idea and reality of a Christian empire long before their kings and grand prince took on and adopted Christianity.