The monograph touches upon problems of source studies, social history and the history of the Christian church in Western Europe that have been little studied in Russian science. The text of the “Acts of the Archbishops of the Hamburg Church”, a work belonging to a German chronicler of the second half of the 11th century, is examined. Adam of Bremen. Some aspects of the history of the Hamburg-Bremen Archbishopric during the era of the northern missions (IX - mid-XII centuries), as well as certain issues of the history of the penetration of the Christian religion into medieval Scandinavia, are considered. The appendix contains translations of several important Latin-language sources covering the Christianization of Scandinavia. An exhaustive bibliography on the topic of research is provided. The book is intended for medieval historians, primarily Scandinavians, specialists in medieval philology, and a wide range of readers interested in the history of Western Europe in the Middle Ages, the history of the Christian Church, and auxiliary historical disciplines.