The scene of _Leoniero da Dertona_ is in the twelfth century. The inhabitants of Dertona, a city which had joined the celebrated Lombard league against the Emperor Frederick, are divided into two factions; one, headed by Arrigo, tribune of the people, taking part with the allies; the other adhering to the cause of the Imperialists. The first party hold a fortress upon the rock, in those times a post of great strength and importance. The consul Enzo, leader of the Imperialists, had given his sister Eloisa in marriage to Arrigo, to induce him to desert his cause; that failing, had treacherously possessed himself of the person of the tribune, threatening to kill him if the fortress were not surrendered. At this crisis, Leoniero, father of Enzo, returns from the East, where he had gone as a soldier in his youth, and suffered long imprisonment. A feud has long existed between his family and that of Auberto, the father of Arrigo; but Leoniero, being informed of the conduct of his son, censures highly his breach of faith towards his brother-in-law, and his treason to his country. Yet he cannot so far forget his private resentment as to declare himself the friend of Auberto, though such a course would have at once subdued the strength of the opposing faction, so dear is Leoniero to his countrymen. He remains neutral for a time, and Enzo meanwhile works upon the fears of Eloisa, who endeavors to prevail on her imprisoned husband to write a letter commanding the surrender of the fortress. Neither entreaties nor threats can move the stern virtue of the tribune, and his father is confirmed in his resolution to maintain his trust by the arrival of a messenger from Milan, who discovers the treacherous alliance of Enzo with the Imperial troops, and promises succor from the Milanese in a few days. Enzo then attempts to possess himself by force of the person of his father, who, finally dismissing his long cherished enmity, takes refuge in the castle with his ancient foe, and is received with open arms. His son sends hostages to induce him to return; and Leoniero, hoping that his paternal counsels may reclaim the traitor, goes, at the advice of Auberto and others, though distrusting his professions of penitence. Arrived at his son’s palace, he finds himself unexpectedly a prisoner, forbidden to see or speak with any but his guards. The fifth act opens with an imposing scene. Upon the walls of the castle are discovered Auberto and his faithful soldiers, the friends of liberty. The plain beyond is filled with Suabian troops, mingled with the Dertonese. In the foreground stands the consul with other magistrates, and the Count of Spielberg, who in the Emperor’s name declares Enzo governor of Dertona, and imposes on all its citizens obedience to him. Enzo kneels to do homage to the vicegerent of his master for his newly acquired domain, and receives a sword from the Count. The senators and his troops swear fealty to him,