Wikipedia
The Janamsakhis (, janamsākhī), literally birth stories, are writings which profess to be biographies of the first Sikh guru, Guru Nanak. These compositions have been written at various stages after the death of the first guru.
The four Janamsakhis that have survived into the modern era include the Bala, Miharban, Adi and Puratan versions, and each hagiography contradicts the other. These mythological texts are ahistorical and do not offer chronological, geographical or objective accuracy about Nanak's life. The Sikh writers were competing with mythological stories (mu'jizat) about Muhammad created by Sufi Muslims in medieval Punjab region of South Asia.
The various editions of Janamsakhi include stories such as fortune tellers and astrologers predicting at his birth that he will start a new religion, cobra snake offering shade to Nanak while he was sleeping, Nanak visiting and performing miracles at Mecca - a holy place for Muslims, and at Mount Meru - a mythical place for Hindus, Buddhists and Jains. At Mecca, the Janamsakhis claim Nanak slept with his feet towards the Kaba which Muslims objected to but when they tried to rotate his feet away the Kaba, all of Kaba and earth moved to remain in the direction of Nanak's feet. The texts also claim Nanak's body vanished after his death and left behind fragrant flowers, which Hindus and Muslims then divided, one to cremate and other to bury. The earliest Janamsakhi was written towards the end of 16th-century, decades after Nanak's death.