 Complete the following phrase:  These arrangements were confirmed and publicly proclaimed in 802, when Harun and the most powerful officials of the Abbasid government made the pilgrimage to Mecca. Al-Amin would succeed Harun in Baghdad, but al-Mamun would remain al-Amins heir and would additionally rule over an enlarged Khurasan. This was an appointment of particular significance, as Khurasan had been the starting-point of the 