Published in 1951, it is based on the medieval verse epic Gregorius written by the German Minnesinger Hartmann von Aue (c. 1165–1210).

Clemens, moved by the "spirit of storytelling" (a term used often in Mann's later works), introduces the reader to the events which led up to the ringing of the bells, i.e., Gregory's arrival in Rome and coronation as Pope.

In Flanders, duke Grimald, seventeen years a widower, is pressing his daughter Sibylla to marry in order to forge an alliance with a neighboring king.

Considering suicide out of shame for what they have done, the brother and sister turn to their loyal counselor, the knight Eisengrein, who suggests that Wiligis take up the Crusade as a means of atoning for his sins.

The Abbot takes the younger Gregory into his cell and shows him the tablet from the barrel, and the young man learns that his mother and father were also sister and brother.

Stunned by the revelation, the younger Gregory resolves to seek out his parents in order to alleviate the suffering he assumes they must feel.

Several years later Gregory's mother discovers the tablet, still in his possession, and realizes that she has married, and borne children by, her own son.

At Gregory's arrival in Rome the bells of city ring out of their own accord, announcing the presence of the next Holy Roman Pontiff.

The author is re-telling an existent medieval text of the Catholic Church that was made morally instructive, and balancing the events through the medium of the sarcastic narrator and his ability to lucidly illustrate the most absurd behavior with no detectable opinion as to how the reader should judge it.