According to a tradition.. and.. in the case of the Persian King is endorsed by Baha'u'llah Himself, Muhammad sent from Medina letters of friendship, proclaiming His prophethood, to.. the Emperor of Byzantium, the Emperor of Persia, the King of Abyssinia, the Governor of Egypt, the King of Hira, the Duke of Yemen.. also to the Emperor of China (in 628 A.D.) (37:3)

End of Quote

Christ & Baha'u'llah
G. Townshend