 Complete the following phrase:  In the Muslim parts of the Horn of Africa, sheikh is often used as a noble title. In Somali society, it is reserved as an honorific for senior Muslim leaders and clerics wadaad, and is often abbreviated to Sh. Famous local sheikhs include Ishaaq bin Ahmed, an early Muslim scholar and Islamic preacher, Abdirahman bin Ismail al-Jabarti, an early Muslim leader in Somaliland; Abadir Umar Ar-Rida, the patron saint of Harar; Abd al-Rahman al-Jabarti, Sheikh of the riwaq in Cairo who recorded the 