Samprati Maharaj existed as a Maurya emperor around 224 BCE to 215 BCE. In Jain accounts he is celebrated as a strong patron of Jainism, credited with building many Jain temples and promoting the religion widely. Different Jain traditions (Digambar/Shwetambar) narrate similar themes about his support for Jainism, though details may vary in specific stories. You can read more about his life and deeds here