The Astronomer and the Witch: uncovering the history of Johannes and Katharina Kepler

Kepler’s model of the solar system

Ulinka Rublack’s book The Astronomer and the Witch: Johannes Kepler´s Fight for His Mother has inspired an opera, performed in Cambridge and Tübingen, as well as a major ‘Hollywood’ film in development.

Based on archival and printed sources, the book tells the story of how the famous astronomer Johannes Kepler (1571-1630) and his family responded to the accusation that their mother Katharina was a witch.

Between 1500 and 1700 in Europe, 73,000 men and women were tried for witchcraft and 40,000 executed. More than half of all victims were executed in the German lands from 1560; 75% of those accused were women.

One of these women was Katharina Kepler, the 68-year-old illiterate mother of the famous astronomer Johannes Kepler, who was accused in the South-West German town of Leonberg in 1615. Katharina vehemently denied the charge and her family were equally outraged. The astronomer took over her legal defence. It took six years for Katharina to be acquitted, by which time she was so frail that she died within months.

In the Anglo-American fiction and non-fiction literature on this trial, Katharina has consistently been portrayed as a witch-like woman. Rublack´s book overturns this account.

She reconstructed Katharina´s life and the belief systems of the time. The book recasts the way we approach the social impact of the witchcraze and how we think about the attitude of a leading natural philosopher towards knowledge. No previous publication had used the trial to discuss Kepler´s understanding of natural philosophy.

The book has been translated into Chinese, Arabic, Italian, Hungarian and German, where it became a listed bestselling book within months, now in its fifth edition, having sold 10,000 copies.

Through documentaries, media appearances, press coverage and the book’s readership, Rublack has changed the way the public in the UK and Germany perceive Kepler and Katharina, and provided fresh insight into the personal and familial effects of the witch trials.

The book led to the creation of an entirely new opera, Kepler´s Trial, which was publicly performed at the Cambridge Festival of Ideas, the Victoria and Albert Museum, and, most recently, in parts and with new additions at Tübingen University, Germany.

In January 2018, the book attracted the interest of acclaimed film director Michael Hoffman and his production company Sympathetic Ink. There has been constant dialogue between Rublack and the writer and director as the script has evolved, and Helen Mirren has confirmed that she will act as Katharina.

“Rublack brings home the challenge and pain of lives pulled apart by the tension between a dying medieval world and the birth of the enlightenment. It was this very human dimension… that made me see in it the potential for a film.”

– Michael Hoffman, Sympathetic Ink film director