Berengario is full of ambition and rage and has sent his son Idalberto to storm the walls of Pavia. He receives news that the German King Lotario is on his way with an army to protect Adelaide. Matilde, Berengario's wife and fully his match in ambition and rage, announces that she has bribed Adelaide's soldiers to open the gates of Pavia to their forces. Her son is truly in love with Adelaide and begs his parents not to do anything that will endanger her, but Matilde will not be moved - Adelaide must marry Idelberto or face death.