Princess Olga of Kiev had asked Emperor Otto I (the Great) to provide her a missionary from the Roman Catholic Church.

Kievan Rus subsequently was converted by missionaries from Constantinople and became part of Byzantine Christianity.

Upon escaping Kievan Rus, Adalbert traveled to the imperial court at Mainz, Germany, where he remained for four years, until he was named Abbot of Wissembourg in Alsace.

[4] The Archiepiscopacies of Hamburg and Bremen had been established with the intention that they would serve as bases for missions in northern and eastern Europe.

[5] Adalbert also established dioceses for Naumburg; Meissen; Merseburg; Brandenburg; Havelberg; and Poznań, Poland.