When the poem begins, Salinguerra has received from the Emperor the badge which gives him the leadership of the Ghibelline party in North Italy.
Then Palma, bringing Sordello to see Salinguerra, reveals to the great partisan that Sordello is his son, and that she loves him.

Salinguerra, seeing in the union of Palma, daughter of the Lord of Romano, with his son, a vital source of strength to the Emperor's party, throws the Emperor's badge on his son's neck, and offers him the leadership of the Ghibellines.

Palma urges him to accept it; but Sordello has been already convinced that the Guelf side is the right one to take for the sake of mankind.

Rome, he thinks, is the great uniting power; only by Rome can the cause of peace and the happiness of the people be in the end secured.

That cause--the cause of a happy people--is the one thing for which, after many dreams centred in self, Sordello has come to care.