The Mughal emperor Babur, visiting Guru Nanak in prison, witnesses the miraculous self-turning millstone, from a manuscript of the Janam Sakhi (Life Stories)

Events from the life of Guru Nanak (1469-1583), founder of the Sikh religion, are recounted in several texts known as Life Stories (janam sakhis). The best-known versions are said to have been based on the recollections of Bhai Bala, one of Nanak's disciples. They contain miraculous and fantastic events intended to create a sense of wonder and emphasize the saint's wisdom and piety.
A frequently repeated episode concerns the encounter between the Mughal emperor Babur (reigned 1526-1530) and Guru Nanak. According to tradition, Babur, in the course of his conquests, sacks the city where Nanak is. All its inhabitants, including Guru Nanak and a disciple, are imprisoned and forced into manual labor. An officer notices that, instead of Nanak carrying a heavy load assigned to him, it is instead miraculously suspended above the guru's head. Hearing this news, Babur visits the prison. Other prisoners are grinding grain by hand at the time, but Nanak's millstone works by itself. The highly impressed Babur (at the lower right corner) subsequently releases Nanak (shown in the yellow robe) and the other prisoners.