Henry III, angry at being denied, immediately laid siege to the city and Pope Clement II excommunicated Landulf and Pandulf and the citizenry.
The siege was eventually lifted, however, the disrespect shown the imperial family and the church coupled with the principality's decline caused Landulf's uncle, Daufer, to flee the city and take refuge with Guaimar IV of Salerno, who housed the religious youth in La Cava.
Beneventan matters came to a head in 1050, when Pope Leo IX went on a pilgrimage to Monte Gargano and reaffirmed the excommunication of the princes.
In April 1051, Cardinal Humbert of Silva Candida and Domenic, Patriarch of Grado, entered Benevento to receive the city on the pope's behalf.
In the aftermath of the Battle of Civitate in 1053, in which the pope was imprisoned in Benevento,[2] the city invited Pandulf and Landulf back (sometime between June 1053 and March 1054).