Founded and directed by the charismatic religious leader and commander of Fassi origin Sayyid Muhammad ibn Ali al-Idrisi, from 1908 to 1930CE, the Idrisid emirate of Asir extended over Jīzān and Tihama in the eponymous province, currently Saudi Arabia and Yemen.
Genealogy
Muhammad ibn Ali al-Idrisi comes from a noble family whose genealogy dates back to Idriss I, founder of the city of Fes and the first Moroccan sovereign. More precisely, he's the grandson of Ahmad bin Idris al-Fasi, a Sufi Islamic scholar from Fez, who studied at the prestigious al-Qarawiyyin University and worked in Morocco and then in the Hejaz region in Arabia.
He marked his era as the founder of the Idrisiyya a set of Sufi traditions and confraternities. Through his followers, he has exerted a diffuse influence throughout the Muslim world. He settled in the town of Zabīd in Yemen, which was a major historical center of Muslim scholarship and died in 1837 in the city of Sabya in what's today Saudi Arabia, which would go on to become the capital of the Idrisid Emirate under the reign of his grandson.
End of the Emirate
After the fall of the Ottoman Empire, the Arabian Peninsula was gripped by internal rivalries and it was clear that England was no longer in a position to honor its commitments, which will constitute a factor in the decline of the emirate.
Moreover, the sovereignty of the emirate of Asir was threatened by the contemplation of Hussein bin Ali, king of Hejaz and by Yemen led by Imam Yahya. The death of Muhammad ibn Ali Al-Idrisi will cause a family quarrel for the throne. Once the new emir al-Hassan came to power, the leaders of Hejaz and Yemen laid claim to Idrisid possessions.
In June 1934, the Saudis and the Yemenis signed a treaty of friendship and brotherhood between Saudi Arabia and Yemen providing for the establishment of peaceful and diplomatic relations between the two countries. The treaty also provided for the demarcation of the borders between the two countries, which was completed in 1936, and thus the lands of the Emirate of Idriss were divided causing its dissolution.
The Idrisi State in Asir: Politics, Religion and Prestige in Arabia | Anne K. Bang | 1997
The Encyclopaedia of Islam (Second Edition) | Headley | 1954-2005