The Prophet's Letter to al-Harith ibn Abi Shimr al-Ghassani

The Prophet sent Shuja' ibn Wahb al-Asadi to deliver a letter to al-Harith ibn Abi Shimr al-Ghassani, the Arab Christian king of the Ghassanid kingdom in Syria, a Byzantine vassal state. The Ghassanids were an Arab tribe who had adopted Christianity and served as the northern buffer between the Byzantine Empire and Arabia. When al-Harith read the letter, he threw it on the ground and angrily declared: 'Who would dare wrest my kingdom from me? I will march to him myself!' He asked the Byzantine emperor Heraclius for permission to attack Medina, but Heraclius refused, ordering him to come to Jerusalem instead. Al-Harith's rejection and hostility would contribute to the growing tensions between the Muslim state and the Byzantine-allied kingdoms in the north, eventually leading to the expeditions of Mu'tah and Tabuk.