This oath of allegiance received, Rienzi, whom matters of state call elsewhere, asks Adrian to remain in his house during his absence, to protect his sister against a renewal of the evening’s outrage.  Adrian joyfully accepts this charge, and the lovers, for they have been such from the very first glance exchanged, remain alone together and unite in a touching duet of faith and love, whose beautiful, peaceful strains contrast oddly with the preceding discordant strife.  In spite of his transport at finding his affections returned, and in the very midst of his rapturous joy at embracing his beloved, Adrian, tortured by premonitory fears, warns Irene that her brother is far too sanguine of success, and that his hopes will surely be deceived.  He also declares that he fears lest the proverbially fickle people may waver in their promised allegiance, and lest Rienzi may be the victim of the cruel barons whom he has now openly defied.  The lovers’ conversation is interrupted at sunrise by the ringing of the Capitol bell, proclaiming that the revolution has begun, and the triumphant chorus of priests and people is heard without, bidding all the Romans rejoice as their freedom is now assured.  Riding ahead of the procession, Rienzi slowly passes by in the glittering armour and array of a Tribune, and from time to time pauses to address the crowd, telling them that the ancient city is once more free, and that he, as chief magistrate, will severely punish any and every infringement of the law.  At the news of this welcome proclamation the enthusiasm of the people reaches such an exalted pitch that they all loudly swear to obey their Tribune implicitly, and loyally help him to uphold the might and dignity of the Holy City:—­

   ’We swear to thee that great and free
    Our Rome shall be as once of yore;
    To protect it from tyranny
    We’ll shed the last drop of our gore. 
    Shame and destruction now we vow
    To all the enemies of Rome;
    A new free people are we now,
    And we’ll defend our hearth and home.’

The scene of the second act is laid in the Capitol, where the barons, who had been forced to take the oath of allegiance ere they were allowed to re-enter the city, are present, as well as the numerous emissaries from foreign courts.  Heralds and messengers from all parts of the land crowd eagerly around the Tribune, anxious to do him homage, and to assure him that, thanks to his decrees, order and peace are now restored.

Amid the general silence the heralds make their reports, declaring that the roads are safe, all brigandage suppressed, commerce and agriculture more flourishing than ever before, a statement which Rienzi and the people receive with every demonstration of great joy.  To the barons, however, these are very unwelcome tidings, and, knowing that the people could soon be cowed were they only deprived of their powerful leader, they gather together in one corner of the hall and plot how to put Rienzi to death.