Kepler's Trial

an opera by Tim Watts based on The Astronomer & the Witch by Ulinka Rublack


An overview of the Opera

Johannes Kepler (1571-1630) is one of the most admired astronomers who ever lived. He defended Copernicus's sun-centred universe and defined the three laws of planetary motion. Less well known is the fact that in 1615, when Kepler was at the height of his career, his old, widowed mother Katharina was accused of witchcraft in a Lutheran town in Germany. The proceedings led to a criminal trial, with Kepler conducting his mother's defence to fight for legal justice. Kepler's Trial responds to Paul Hindemith's Opera Harmony of the World and other accounts which present Katharina Kepler as deranged, witch-like woman. Based on Ulinka Rublack's book The Astronomer & the Witch the opera explores with empathy and nuance what it meant for Johannes and Katharina to face the trauma of an accusation of witchcraft, before and after the trial. The opera is the culmination of a highly unusual creative process, in which a team of leading scholars met regularly to explore the story. The film tells the story of the project, which has been funded by St John's College Cambridge and Cambridge University and is directed by Ulinka Rublack. Since the premiere in 2016 it has been performed at the Victoria & Albert Museum as part of the 2017 exhibition ‘Opera: Passion, Power and Politics’. Both full productions were directed by William Ashford and conducted by Graham Walker. Extracts of the opera have also been toured to Tübingen (Kepler’s university town) and Munich in 2019.


Drama, intrigue and 17th century drinking songs

Katharina is put centre-stage through the use of as many of her own recorded words as possible, supplemented in the case of her first appearance in the opera with a contemporary rhyme on the ages of womankind, which she utters as a reflection on her plight. These are fragments of her own voice – prayers, responses to cross-examination – preserved in trial transcripts. These glimpses of her personality, her faith and her resilience under cross-examination are tiny snapshots, but, in the necessarily constricted word count of a libretto they become substantial, set-piece statements.

Two Lutheran chorales (both with music by Melchior Vulpius) are further examples of primary source material used in the opera to evoke the Leonberg community's fear of darkness.

In prison, Katharina sings a psalm in the eloquent words of the King James Bible. Its Shakespearean qualities also provide a stylistic source for much of the invented portion of the text. Kepler is envisaged as a tragic, prophetic figure, thundering against superstition. His words frequently allude to the planetary preoccupations of his work (although not to the same extent as in Hindemith’s Die Harmonie der Welt, in which the third law of planetary motion is set to music).

The opera is framed by visitations from a Daemon. This character is Kepler’s own literary creation, used in the preface to his strange work of proto-science-fiction, the Dream, to provide the supernatural means for a mother and her son to fly to the moon.

Professor Simon Schaffer and Professor Nick Jardine review the creative process of how the libretto was made.


Why Opera?

Opera was born during Kepler’s lifetime. It defined a notion of modernity just as Kepler’s work inhabits another one intellectually. It celebrated the power of music, as an enhancement of speech and sometimes a substitute for it. In his writings, Kepler understands the effect of music on human emotion as linked directly to its embodiment of cosmic harmony. We vibrate in sympathy to its evocation of divine order and respond equally to the disruptions to this order generated by dissonance. His insistence on the interconnection of sensory experience and the organisation of the universe makes his worldview intrinsically operatic. Like Kepler, Claudio Monteverdi, the composer of the one of the earliest operas, L’Orfeo (1607), was a figure who existed on the cusp of the transition from the old to the new. Both also met with hostility from those who viewed their ideas as a threat to established traditions.

The variety of vocal and instrumental forms and textures of L’Orfeo, which juxtaposes recitative, arioso, ritornello, dances and madrigalian choruses, is one of the models for the opera, along with the passions of Bach, which are reflected in the presence of chorales and the contrapuntal style of some of the choral interjections. Musical ‘found materials’ such as the drinking song, modelled on examples by Johann Hermann Schein, are used not just for historical flavour, but for the ways in which they can be transmuted ‘alchemically’ into new and unfamiliar things, taking on new meanings and emotional weight within the world of this story.

Composer Tim Watts discuss his inspiration behind the music for the Opera.

Schein’s drinking song ‚‘Ihr Brüder, lieben Brüder mein’ and the madrigal based on it from the first scene of Kepler’s Trial, both performed by Gesualdo Six.

Second Interlude: Sun and Shadow

For the 2017 production at the Victoria & Albert Museum, Watts composed a new interlude based on an alchemical canon composed by Michael Meier, court physician to Rudoph II in Prague during Kepler’s time as Imperial Mathematician. A new vocal line (here performed by Hamish McLaren with Gesualdo Six) acts as a kind of musical graffiti over the historical source material that recontextualises and brings it into tension with the style and narrative of the opera into which it has been introduced.

Kepler is introduced with the support of a sonorous quintet of cornetts and sackbuts, while Katharina’s isolation and fragility are coloured, when we first meet her by a harpsichord.

In 2019 the University of Tübingen commissioned a group of four Kepler-Motetten from Watts, in which Kepler’s ideas of cosmic harmony and the planetary chorus are embodied in a vocal sextet (performed by Gesualdo Six). In these motets, Kepler’s pursuit of harmony is placed alongside words from the German Romantic poets Novalis and Hölderlin, for whom Kepler occupied a heroic position as one who intellectually illuminated the night sky. Like its elder ‘sibling’, Kepler’s Trial, the motets weave in references to the music of Kepler’s time, most strikingly through its use of the Lutheran hymn, ‘Wie Schön leuchtet der Morgenstern’.

Overview of the Tübingen performance in 2019.


Knowledge, Illusion and the Figure of the Aged Woman

Dr Victoria Avery, Keeper of Applied Arts at The Fitzwilliam Museum, Cambridge talks talks about the German Renaissance sculpture of the old woman which inspired Ulinka and Aura.

The film elements in the opera by Aura Satz are a response to Ulinka's book and Tim's opera libretto, as well as the many ideas that emerged through the meetings at St John's College, Cambridge. It features a selection of objects from the Whipple Collection for the History of Science and the Fitzwilliam museum. Many of which were filmed rotating on a hand-cranked turntable. This became a key structural device, an illustration of Kepler's cosmological interests, but also as a formal means of shifting, inverting or reconceptualising viewpoints, from Kepler's voice to that of his mother. It resonates also with the lenses and mirrors of featured optical devices such as the telescope and the camera obscura, as well as with a naturalistic German Renaissance sculpture of an old woman and the fearful imagination of old witches at the sabbath, by the early seventeenth-century Dutch artist van Gheyn.


Johannes Kepler: A unique scientist

Kepler is often seen as a champion of rational thinking that mechanized the universe. In fact, our neat distinctions between religion and magic, the rational and irrational obscure how knowledge about nature and humans mattered to him. This in turn explains connections between some of his ideas and those of his mother. Both saw the earth as alive and the micro- and macrocosm as interlinked. What happened to a living tree or star, might register in your body. Above all, the world was always God's creation, and Kepler was inspired by the belief that nature could reveal traces of God as its maker. Humans were created in God's image. Musical octaves even touched 'ignorant folk', and dance-steps followed geometrical patterns. The world was something far more fascinating than a mechanical clock-work, and Kepler's interest in music was related to his fascination both with regularity as well as surprise, creativity and renewal. In contrast to many at the time, Kepler wrote nothing about the devil as a force. Instead he politically championed the possibilities of religious peace and social advances through new learning. The accusation that he might have been raised by a woman bound to the devil was particularly shocking for him in this sense.

Professor John Toland explains why Johannes Kepler is one of the most important astronomers of all time.


Key dates in Johannes Kepler's Life, 1571-1620

  1. 1571

    Johannes Kepler born on 27 December in Weil der Stadt; his parents are Heinrich Kepler and Katharina Kepler, née Guldenmund.

  2. 1575

    The Kepler family moves to nearby Leonberg, in the Lutheran territory of Württemberg.

  3. 1578

    Johannes Kepler enters the local Latin school.

  4. 1579

    The family moves to Ellmendingen in Baden.

  5. 1583

    Johannes Kepler returns to Leonberg and passes a scholarship exam in Stuttgart.

  6. 1584

    Johannes enters the elite boarding school in Adelberg.

  7. 1586

    He changes to the elite boarding school in Maulbronn.

  8. 1589

    Johannes inscribes himself at Tübingen University.

  9. 1590

    His father Heinrich dies.

  10. 1591

    He receives his first degree and remains in Tübingen to study theology.

  11. 1594

    Johannes Kepler starts teaching mathematics teacher at the Protestant school for aristocratic sons.

  12. 1596

    Kepler publishes his first book, the ‘Cosmographical Mystery',Mysterium.

  13. 1597

    He marries the Lutheran Barbara Müller.

  14. 1598-1600

    Johannes and Barbara are forced to leave Graz in October 1600.

  15. 1600

    Johannes Kepler collaborates with Tycho Brahe.

  16. 1601

    Publishes Apologia Tychonis contra Ursum.

  17. 1601

    Tycho dies, and Rudolf II appoints Kepler as Imperial Mathematician.

  18. 1602

    birth of his daughter Susanna.

  19. 1604

    Publishes his treatise Astronomia pars optica.

  20. 1606

    Publication of De Stella Nova (On the New Star).

  21. 1607

    birth of his son Ludwig.

  22. 1609

    Johannes Kepler travels to Württemberg; publishes the ‘New Astronomy’, Astronomia Nova; and a treatise on astrology, Tertius interveniens.

  23. 1610

    He responds to Galileo´s discoveries in his Dissertatio cum nuncio sidereo.

  24. 1611

    Barbara Müller dies; publishes Dioptrice.

  25. 1612

    Rudolf II dies.

  26. 1612

    Johannes Kepler has to leave Prague with his children because of the Counter-Reformation and finds a new position as mathematician for the Inner Austrian Estates in Linz.

  27. 1613

    He marries his second wife, Susanna Reuttinger.

  28. 1615

    Katharina Kepler is accused of witchcraft.

  29. 1617

    Johannes Kepler travels to Württemberg to help his mother.

  30. 1617-19

    Ephemerides Novae.

  31. 1618

    Beginning of the Thirty Years´ War; Kepler begins to publish his textbook Epitome Astronomiae Copernicanae.

  32. 1619

    Publishes his major work ‘Harmonies of the World’, Harmonices Mundi.

  33. 1620

    Johannes Kepler travels to Württemberg to defend his mother.


Reviews of Kepler’s Trial at the Victoria & Albert Museum, November 2017

‘The production boasts remarkable intellectual, musical and staging coherence… The opera tackles old women’s vulnerability to injurious representations, but also explores the disconcerting indefiniteness of the line between reason and delusion, science and magic, light and darkness, the personal and the cosmic, harmony and dissonance, which feature in Kepler’s life and work…All of these elements flow into a musically and dramatically compelling production. At the core of the emotional tension are Katharina and Johannes’s relationship with each other, and their clash with the superstitious society around them.’

(Valeria Vescina, seenandheard-international.com)

Watts’s writing for his 13-strong ensemble (crisply conducted here by Graham Walker) is wonderfully limpid—peer through the glossy surface provided by a string quartet and you catch glints of jewel tones from harp and flute, but also the muddied, gritty textures of sackbut and cornetts. Weaving these early instruments along with ‘found’ scraps and sections of music from Lassus, Vulpius and Schein into the score, Watts nods to Kepler’s age without getting bogged down in pastiche. Patterns and themes cycle and intersect like the astronomer’s orbiting planets, anchoring the score structurally.

(Alexandra Coghlan, Opera Magazine)

Reviews of Kepler-Motetten, 2019

‘Everything was interconnected - in precise correspondence to Johannes Kepler's new, but still Christian-devout Copernican world view at the epochal turning point towards the modern age and located between mathematics, mysticism and magic. In addition to the German-British exchange on the subjects of literature, music and (historical) science there was a British variation on the subject of Kepler's sense of humour making this a most wonderfully enjoyable event in the age of Brexit. This was confirmed by the enthusiastic applause and the delightfully cheerful atmosphere during the reception that followed.’

(Martin Bernklau, Reutlinger General-Anzeiger)

‘dissonant tight clusters, compressed agglomerations of sound overlaid by irridescently sweet counter sonorities…transposition of the earth's orbit into sound frequencies…rising suns of sound…artistically accomplished and sonorous…Dissonance gives rise to harmony and vice versa - altogether remarkable, philosophically and compositionally advanced music.’

(Achim Stricker, Schwäbische Tageblatt)

‘the desperate beauty of the second motet of Tim Watts’ sublime Kepler-Motetten…was an echo in darkness…Gesualdo’s harrowing rendition evoked a sense of cosmic loss and isolation as near total as that vouchsafed in permanent exile. I was minded, apropos of the plaintive desolation of the voices, to think of the forsaken godlessness of a Beckett play, if not also of Friedrich Hölderlin, the German Romantic poet whose luminous lines inform Watts’ music.’

(Steve Whitaker, Yorkshire Times)

Praise for The Astronomer and the Witch

Ulinka Rublack shows wonderful sensitivity about mothers, old age, and female struggles, as she unpicks the trial of Johannes Kepler's mother for witchcraft. (Marina Warner, Book of the Year 2015, Observer)

Excellent ... meticulously researched and wonderfully readable. (John Banville, Literary Review)

[A] superb study ... The author wanted her book to provide a "better understanding of individuals, but also of families, a community, and an age". It succeeds triumphantly. (Jonathan Wright, Catholic Herald)

In 1615, an illiterate widow is accused of witchcraft in a German town. Her son, the famous astronomer Johannes Kepler, conducts her defence in a trial that drags on for six years. In this enthralling book, Ulinka Rublack reconstructs the struggle over Katharina Kepler's fate. We enter a small-town world of rivalries, friendships, deference, power and vulnerability, a world in which religious faith, scientific knowledge and folk belief are dangerously intertwined. Vividly drawn and subtly observed, The Astronomer and the Witch opens a window onto the inner life of a past that is strange and remote, but also unsettlingly familiar. (Christopher Clark)


Performing materials

  • Kepler’s Trial Information sheet
  • A concise overview of the background to the piece and the vocal and instrumental forces required to stage it.

    Vocal Score

  • A PDF vocal score is available to download free of charge here. Full scores and parts are available directly from Tim Watts at tjw33@cam.ac.uk.
  • Synopsis

Education resources

Extracts from Johannes Kepler’s legal defence of his mother, translated for the first time into English by Pamela Selwyn, with generous support of St John’s College. For the context of his defence see Ulinka Rublack, The Astronomer & the Witch, Oxford University Press, chs 11 & 12. The document has been cut to make it more readable for non-specialists: a scholarly edition of the full document and its legal citations is in progress. The purpose of this resource is to document in English the intensity of Kepler’s involvement in the trial and how he applied his ability to refute opponents in scientific arguments and argue for fact based procedure to legal proceedings in which his mother’s life and own reputation were at stake.
Ulinka Rublack

Read extracts from Johannes Kepler’s legal defence. (PDF)

Workshop plans for Kepler’s Harmonies Outreach project developed with the Faculty of Music, University of Cambridge.

Information about past performances, creative team and collaborators


For talks at schools and communities about the project in relation to the German Reformation, Johannes Kepler and the history of women and old age please contact Ulinka at ucr10@cam.ac.uk