In December 1615, the renowned astronomer Johannes Kepler first received news that his elderly mother, Katharina, had been accused by a neighbour of witchcraft. A victim of the witch craze that swept through early seventeenth-century Germany, Katharina’s torment lasted for six long years, during which time Johannes temporarily abandoned his research to concentrate on building his mother’s defence. After being subject to a humiliating criminal trial and serving a spell of more than a year in prison, Katharina was finally exonerated in September 1621. This was an ordeal from which she never recovered: Katharina died just six months later aged seventy-six.
On 28 and 29 October a new opera telling Katharina’s story premiered in the chapel of St John’s College, Cambridge, as part of the annual Festival of Ideas. Since 2008, the Festival has sought to bring the research of Cambridge academics working in the arts, humanities, and social sciences to a wider public through a series of lectures, workshops, exhibitions, debates, and theatrical performances. True to form, Kepler’s Trial is a dynamic and exciting production, which testifies to the creative possibilities of interdisciplinary collaboration and public engagement.
This new telling of the Kepler family’s crisis is based on Ulinka Rublack’s important recent rehabilitation of Katharina in The Astronomer and the Witch (Oxford, 2015), with a libretto and score by Tim Watts and filmic elements by Aura Satz using objects held in the collections of the Fitzwilliam Museum and the Whipple Museum of the History of Science. Both the programme and the project website also credit participants from the Faculties of History, Music, History and Philosophy of Science, as well as a host of scholars and artists from outside Cambridge.
The production, like Rublack’s book, encourages the audience to meditate upon the trauma that witchcraft accusations could visit upon whole families and not just the accused. Much of the story is explored through the mother-son relationship and opera is the perfect medium to give expression to the intense emotions at stake in Katharina’s trial. But this is also a piece that brings alive the wider world of early seventeenth-century Germany. The position of women in early modern society is an important theme: at seventy years old, Katharina is ‘barren and grown cold’ and requires ‘an educated man to read and write on her behalf’. But Kepler’s Trial is equally concerned with aspects of Johannes Kepler’s experience that have often been neglected in previous accounts of his life. Kepler believed in magic, the devil, and witchcraft. The opera derives a great deal of power from the way it plays with the deeply felt and sometimes contradictory emotions rarely associated with a man of science.
This is a production in which every element has been carefully considered with these larger themes – science and magic, mothers and sons, darkness and light – in mind: on their website, the creators draw our attention to the sextet of violins, for example, which function as ‘six, individual planets, perhaps, functioning as a mini-solar system within the whole ensemble’ or film footage of images and artefacts – a statue of an old woman, telescopes and other optical devices – which rotate constantly, serving as ‘an illustration of Kepler’s cosmological interests, but also as a formal means of shifting, inverting or reconceptualising viewpoints’. 
Seeing the opera, I was both astounded by the incredibly rich vision to which Rublack, Watts, Satz, and their collaborators had given life and felt certain that I must be missing some of these subtleties in the music and staging. A production that stands testament to the exciting possibilities of truly interdisciplinary collaboration and confronts its audience with the opinions, passions, and worldviews of a variety of different characters – Johannes, Katharina, her neighbours and accusers – Kepler’s Trial is quite literally an example of both doing history for the public and doing history in public. We can only hope that Kepler’s Trial is revived for future performances so that more audiences can both enjoy and learn from it.
 Quotes taken from Scenes 2 and 3 of Kepler’s Trial. The full libretto is available at http://keplers-trial.com/keplers-trial-libretto.pdf.
http://keplers-trial.com (including the full libretto at http://keplers-trial.com/keplers-trial-libretto.pdf)
Ulinka Rublack, The Astronomer and the Witch: Johannes Kepler’s Fight for His Mother (Oxford, 2015).
Albrecht Dürer – copperplate circa 1500, Public Domain, https://commons.wikimedia.org/w/index.php?curid=11854515