English summary: The history of Christianity in Poland, and thus of the first contacts with the Roman Curia as well, may be traced back to the second half of the 10th century. In 966 Duke Mieszko I was baptized, and the first missionary diocese was set up in Posen. Further dioceses were to follow in Prague and Olomouc, in addition to the many monasteries from various orders which were then established. This volume analyzes the contacts of...