Theiss of Kaltenburg was an 80 year old man of Livonia, tried for heresy in the late 17th century.
He claimed to be part of benign cult of Werewolves who fought the devil and brought back stolen grain and property.
The judges in the case did not agree with his defence, and he was sentenced to flogging and banishment.
Historian Carlo Ginzberg, in his 1966 paper “The Night Battles: Witchcraft and Agrarian Cults in the Sixteenth and Seventeenth Centuries” suggested this was linked to the agrarian Benandanti cult of Northern Italy. He further theorised that it was evidence of an ancient shamanic shape shifting cult.
Unfortunately an interesting story does not always make for the best theory and Ginzbergs intriguing hypothesis has been strongly criticised; most notably by Dutch historian Willem De Blécourt in his 2007 paper “A Journey to Hell: Reconsidering the Livonian “Werewolf””.
However, recently Bruce Lincoln gave a measured reappraisal of the notion. In his 2015 Hayes-Robinson lecture ‘The Werewolf, the Shaman, and the Historian: Rethinking the Case of “Old Thiess” after Carlo Ginzburg’
Full audio of Lincoln’s lecture can be found here:-