 Personalities, amongst others, included the Negus of Axum, Heraclius (emperor of the Byzantine Empire), the Muqawqis of Egypt, Khosrau, Sassanid King of Persia (Iran).There has been controversy amongst academic scholars as to their authenticity.According to Forward, academics have treated some reports with scepticism, although he argues that it is likely that Muhammad had assumed correspondence with leaders within the Arabian Peninsula.