ATERSE Argument chops up history more than usually fine. ‘At the Time that the Empress Ariadne, Widow of Zenon, raised Anastasius to the Empire, Vitalian the younger stirred up Asia Minor, and coming with a powerful Army, pass’d the Thracian Bosphorus, and besieged Constantinople. At the same Juncture Justin, leaving the Plow, entered the Field in favour of the Greek Emperor; and taking Vitalian Prisoner, he was deservedly crowned with the Imperial Laurel. On the foregoing Passages the present Drama is wrought.’

Act I opens in A magnificent Hall, prepared for the Coronation of Anastasius: Anastasius and Ariadne seated on the Imperial Throne. A Court of Knights and Ladies – Guards and Populace – A Band of Instruments on the Stage. Whilst Ariadne is crowning Anastasius with the Imperial Laurel, a chorus hails his reign as a future golden age. Amanzio, ‘General of the Imperial Arms’, warns them of the danger from Vitaliano. Anastasio wants to fight and goes to rise, but Ariadne withholds him. Polidarte, Vitaliano's envoy, enters with Attendants and offers peace in return for Arianna's hand in marriage to Vitaliano. Anastasio sends a defiant reply, and Arianna resolves to join him at the front. The set changes to A Country with Fruit-Trees, Justin with his Plow. He longs to leave agriculture for warfare but feels drowsy and lies down on his Plow to sleep. A gay Symphony, the Scene is suddenly brightened, and Fortune sitting on a Wheel which turns, descends in a grand Machine attended by Genii, who bring in their Hands Sceptres, Crowns, and Treasures. Fortune, echoed by a chorus of Genii, bids Giustino wake up, forsake cottage and meadow and go forth ‘to grace a Palace and adorn a Throne’, assuring him of her support. Fortune disappears, and Justin awakes and rises hastily. No sooner has he resolved to obey the summons than going out he meets Leocasta pursued by a Bear. He attacks the Bear and kills him. Leocasta, discerning ‘a Soul ill-suited to his homely Dress’, informs him that she is the Emperor's sister and invites him to Court. In An Apartment Arianna orders Amanzio to follow her to Anastasio's camp. Amanzio bids Fortune favour his deceitful plan.