According to al-Tabari in his History of the Prophets and Kings, Muhammad decided after the Treaty of Hudaybiyyah to send letters to many rulers of the world, inviting them to Islam.

Muhammad, according to traditional Islamic historiography, sent ambassadors with such letters to Heraclius the Caesar of Byzantium, Chosroes II the Khosrau of Persia, the Negus of Abyssinia, Muqawqis the ruler of Egypt, Harith Gassani the governor of Syria, Munzir ibn Sawa and to the ruler of Bahrain.