This volume contains 10 texts revolving around the establishment and the earliest operations of the Poznań bishopric including Christianisation of Mieszko I (966), the first ruler of Poland and summoning to the country Jordan (968), the first Polish bishop. The authors focus on analysing the sources, looking for the roots of the first Polish bishopric and the oldest sacral architecture, the origin and legal status of the first bishops as well as the contexts of archaeological research. The events have been presented against a broader comparative background encompassing not only the early Church and its development but also the vast context of political history of that time.