Bertalda’s parentage is revealed at her name-day feast, where Undine’s songs transform a private history of loss into a public recognition. The discovery overturns Bertalda’s belief in her noble birth: she is the infant lost by the fisherman and his wife, while Undine, found in their cottage on the same night, had been raised in place of their drowned child. The revelation reunites Bertalda with her birth parents but does not immediately reconcile her to them, exposing the friction between biological kinship, years of fosterage, and social rank.

The histories behind the revelation

The event reaches back about fifteen years, to a day when the fisherman was away crossing the forest on his way to the city. His wife stayed at home with their newborn daughter. The couple were poor, and the fisherman had been considering whether they should leave their cherished home and move somewhere more suitable for bringing up the child. On his return, however, his wife met him in mourning: their infant had disappeared into the lake.

She had been sitting beside the water with the child when the little girl leaned toward something that seemed to attract her, laughed, and reached out her hands. In an instant she sprang from her mother’s arms and sank beneath the surface. The fisherman searched for her without finding any trace. That same evening, the bereaved parents sat together in their cottage when a richly dressed little girl, wet from the water and only three or four years old, appeared at their door. They took her in, warmed and cared for her, and decided to raise her in place of their lost child. This foundling was Undine.

The couple could not establish Undine’s parentage or whether she had been baptized. She said she had been called Undine by her parents and wished to keep that name; after consulting a priest, the fisherman arranged for her baptism in the cottage. Their adoption was an act of care amid grief, but it also left the original infant’s fate unresolved. At the feast, the songs Undine sings supply the missing account: the child the fisherman and his wife mourned had survived and become Bertalda.

Undine makes a private loss public

The revelation unfolds at a lavish dinner held in Bertalda’s honor. She sits between Undine and Huldbrand, adorned with flowers and jewels given by her foster-parents and friends. After the meal, the doors are left open according to an old German custom, allowing ordinary people to watch the nobles’ celebration. Undine has promised an explanation, and Bertalda and Huldbrand wait for it, watching her as she delays with a smile, apparently struggling to hold back the secret.

When guests ask her to sing, Undine has her lute brought. Her first song recalls a mother’s happiness with her infant and the child’s sudden loss; its closing image of a priceless joy left on an unknown shore prompts Bertalda’s foster-father to recognize the story as the circumstances of the morning he found her. Undine then resumes the lute to sing of the bereaved parents’ search. The songs work as more than a performance: they bring together the child’s two histories—the discovery by the foster-parents and the unanswered grief of the birth-parents—before the assembled company.

Bertalda understands that Undine knows more than she has yet said. Weeping, she asks where her parents are and scans the gathering, at first seeming to expect that they might be people of high rank. Undine turns instead toward the doors and asks where the waiting parents are. The old fisherman and his wife step forward from among the spectators. Their uncertain gaze moves between Undine and the young woman presented as their daughter; the duchess recognizes Bertalda as the infant found years earlier. The parents embrace her, weeping and praising God.

Recognition and resistance

Bertalda tears herself away from the embrace. The recognition collides with her expectation that her former splendor might be increased, and she interprets the scene as a deliberate humiliation staged by Undine. She denounces Undine and the old couple, calling them deceivers and impostors, while the fisherman’s wife privately grieves that the child she has recovered seems wicked. The fisherman, unable to accept the possibility that his daughter could behave this way, silently prays that she is not his child.

Undine is pale and shaken. She had imagined the revelation as a source of happiness, but Bertalda’s rejection turns that hope into fear and distress. She repeatedly asks whether Bertalda has a soul, as if trying to rouse her to recognition of what has happened. With the company beginning to dispute and take sides, Undine asks to speak in Huldbrand’s hall. Her request briefly stills the gathering, but Bertalda continues to deny the evidence and asks her noble foster-parents to remove her from a company she regards as insulting her.

The duchess refuses to leave without establishing the truth. The fisherman’s wife offers a specific test: Bertalda has a violet-like mark between her shoulders and another on the instep of her left foot. Bertalda refuses to uncover herself before a peasant woman, but the duchess directs her to go into a private room with the woman. When the three return, the duchess confirms that both marks match and declares Bertalda to be the fisherman’s daughter. The marks turn a contested family history into an identification publicly affirmed by the highest authority present; Bertalda can reject the parents, but not the evidence.

Consequences and significance

The princely couple leave with Bertalda, and the fisherman and his wife follow them. The guests disperse in silence or private murmuring, while Undine sinks weeping into Huldbrand’s arms. The gathering therefore ends with recognition but not a simple restoration: Bertalda’s birth family has been found, yet the young woman resists the kinship the gathering has established, and her foster-parents remain part of the family history the revelation has exposed.

Undine soon offers a way forward. She invites Bertalda to come with them to Ringstetten Castle and asks her not to address her as a noble lady. She describes the two women as having been exchanged in childhood and proposes that they strengthen their kindred destiny by sharing what they have as sisters. Huldbrand supports the invitation and offers Bertalda his hand, while tactfully refraining from speaking further about the fisherman and his wife when he sees that their names distress her. Bertalda accepts their care, and the three leave the city together.

The episode makes identity depend on several forms of belonging that do not neatly coincide. Bertalda’s upbringing among the princely couple has given her a noble social position; the identifying marks and the parents’ testimony disclose her birth; and the years of care by her foster-parents remain part of the life that disclosure cannot erase. Undine, herself raised by the fisherman and his wife after arriving as a stranger, is the one who assembles these histories and attempts to turn revelation into kinship rather than punishment. Later, at Huldbrand’s funeral, Bertalda remembers Undine’s kindness in wishing to give her a coral necklace on the Danube, a reminder that the hostility at the feast does not exhaust the complicated bond between them.