The opera is based loosely on the events of the Roman invasion of Germany in the year 9AD.

Act I

Arminio, a German prince, retreats from the battlefield as his wife Tusnelda begs him to flee the invading Romans so that he can live to fight another day. Although at first reluctant, Arminio agrees when Tusnelda fears they might both be captured.

Varo, the Roman general, enters with the tribune Tullio. Tullio reports on the departure of Arminio, and Varo reveals that he loves Tusnelda. Tullio tells him to abandon such romantic hopes and fight instead for honour and glory. Varo responds by telling him that love can inspire a man to act with honour.

Arminio is now brought in as a captive of Segeste, another German prince, and Tusnelda’s father. Arminio upbraids Segeste for his betrayal of both his country and his family. Tusnelda considers the dilemma of conflicting loyalties, and departs. Varo demands Arminio’s subjection to Rome, but he proudly resists and prefers death. He is led away defiantly and Segeste insists that unless Arminio submits he will be killed, as there will never be peace with Rome while Arminio lives.

In Segeste’s castle, his son Sigismondo contemplates the meaning of his dreams. He is in love with Ramise, Arminio’s sister, who now enters with Tusnelda. Tusnelda tells them of Segeste’s treachery, and Ramise leaves in despair for her brother’s fate. Sigismondo turns to Tusnelda for sympathy, but she points out that her own troubles are even worse than his, torn as she is between her love for her father and her husband.

Segeste enters and tells his son to give up all hopes of his love for Ramise. Sigismondo refuses to accept this, and says he would rather die than live without love.

Act II

Segeste learns of Varo’s love for his daughter Tusnelda, and looks forward to their union once Arminio is dead. Varo presents Segeste with a letter from the Roman Emperor Augustus, demanding the execution of Arminio to complete Rome’s triumph over the Germans. Segeste looks forward to carrying out this order.

Once more Arminio faces demands to recognise Rome’s victory, and again he refuses. He will face death without fear, but Segeste will have to live with the shame of betraying his country. Arminio is dragged away to prison to await his death. Tusnelda enters in distress, and Segeste advises her to save her husband by persuading him to change his mind, but she refuses.

Ramise now enters and abuses Segeste, before lunging at him with a dagger. But she is disarmed by Sigismondo, leaving Segeste even more determined to execute Arminio. Ramise now berates Sigismondo for thwarting her attempt on Segeste, but he says he cannot stand by to see his own father killed. He takes the knife and attempts to stab himself, but Ramise instinctively stops him. Confused by her divided loyalties, she leaves.

In prison, Arminio tells Varo that he has known about his love for Tusnelda, and to their surprise hands her to Varo. He leaves them, prepared to face his death. Tusnelda tells Varo that the only way he can please her is by saving Arminio. He leaves to do this, and Tusnelda reflects that in doing so he will save two lives and earn her gratitude.

Act III

Arminio is led to the place of execution but is not intimidated into recognising Rome’s victory. His death, he hopes, will deal a fatal blow to Roman pride. Varo, to Segeste’s surprise, has Arminio’s chains removed so that he can die as a soldier on the battlefield. Tullio arrives with news of a Roman defeat at the hands of another German prince, and Varo orders Arminio’s return to prison as he returns to the battelfield. Despite his incarceration, Arminio is given hope by the Roman defeat. Varo leaves Segeste to defend the castle.

Elsewhere in the castle, Tusnelda has decided on suicide. She firstly contemplates Arminio’s sword, but choses instead to take poison. As she is about to drink Ramise enters and stops her. She tells Tusnelda that while Arminio still lives they have a duty to save him and revenge his captors.

They go to Sigismondo and ask him to release Arminio. When he refuses they threaten suicide – Tusnelda with the poison and Ramise with the sword. Sigismondo stops them both, and exits still confused by his conflicting loyalties. The two women comfort each other in their despair, but are interrupted by Arminio who is now free from prison. Sigismondo returns with Arminio’s sword, which he has previously snatched from Ramise. He gives the sword to Arminio who rushes off to engage the Romans in battle, followed by Tusnelda. Ramise is concerned for Sigismondo’s safety when Segeste discovers what he has done, and entreats him to flee. But Sigismondo decides to stay and face his father.

Segeste now enters and vents his fury on Sigismondo, who offers his father his own sword to kill him. To defend him, Ramise claims that it was her who released Arminio. Segeste has them both put in chains and storms off, and Sigismondo and Ramise are taken away by the guards.

Tullio tells Segeste that Varo has been defeated by Arminio and is dead, and that his own castle has been taken. Tullio suggest that they flee, while Sigismondo stays to defend his father, who dismisses him as a traitor. Arminio enters with Tusnelda and disarms Segeste. Sigismondo and Arminio beg Segeste to end his anger, and offer to spare his life if he does. Overcome by their virtuous offer, Segeste agrees and embraces Arminio.

Arminio gives his sister Ramise in marriage to Sigismondo and all join in a final chorus of rejoicing.

(c) Handel House Museum