Al-Mahdi Abdallah (1793 - 28 November 1835) was an Imam of Yemen who ruled from 1816 to 1835. He belonged to the Qasimid family, descendants of the Prophet Muhammad, which dominated the Zaidi imamate of Yemen from 1597 to 1962. He was also the Imam who executed the famous Sheik Ali bin Abdullah Alshaif. This execution caused the brother of the deceased, Hussien bin Abdullah Alshaif, to rally the tribes of northern Yemen: Hasid, Bakil and Mudhaj. These tribes led an invasion of Sanna, capturing Al Mahdi Abdullah in the process. They used ladders given them by the Shariff of Beihan to climb the walls of Sanna. When captured by Hussien, the Imam ordered that Hussien's father, Abdullah, be released from prison in fear for his own life. When Abdullah entered the palace and saw his son Hussien about to kill the imam, his father yelled "Have mercy on your İmam, Hussien". Hussien said to his father "But he killed my brother!" His father took his jambia off and cut off his beard (a sign of begging in the very north tribal parts of Yemen). His son dropped his sword, sparing the Imam. The imam said "Ask for anything, Hussien." Hussein said, "I want to be the Governor of Ibb." (Yemen today) Hussein also asked to be Governor of Hajjah and Dhale, where a lot of the tribes came from. A lot of Bakil settled in Ibb and stayed. His son Adulwahab and his brother's sons ruled over Ibb until the late 1800s when they were expelled by the Ottomans. The Alshaif dominance in these areas still holds sway today. The Imams used the Alshaif family as a defense from the people of Yemen from that time forward. They believed the family would work against them if they didn't work for them. In 1908 Sheik Naji bin Abdulwahab bin Hussien Alshaif led the war against the Ottomans, taking Sanna, and placing Imam Yahya back in power.
Return of the Tihamah
Abdallah bin Ahmad was one of about twenty sons of Imam Al-Mutawakkil Ahmad. After the death of his father in 1816, he successfully claimed the Imamate under the name Al-Mahdi Abdallah. A British surgeon visited him in 1823 and described him as a tall, slender man of dark complexion. He was reputed to have an excitable nature and changed his ministers with great frequency. His government was portrayed as very weak. The imam had to pay large stipends to various tribes in order to prevent them from plundering the land. However, the local shaykhs grew more assertive over time, and demanded higher subsidies. This had become apparent when a crisis broke out in 1818, after al-Mahdi had mistreated errands from the Bakil tribe. As a consequence, the northern tribes entered San'a, and plundered for 22 days. Only when Al-Mahdi promised to pay 120,000 Riyals did they withdraw.
The time when al-Mahdi Abdallah took over power was a turbulent one. The politico-religious Wahhabi movement had intervened in Yemen since 1803, and the area controlled by the imam had shrunk critically. Parts of the lowlands, Tihamah, stood under the chief of Abu Arish, Sharif Hamud, who took an independent position and sometimes supported the Wahhabi ruler. When Hamud died in 1818, he was succeeded by his son Ahmad. Ahmad allied with the Saudi family, leaders of the Wahhabi movement, in order to fight the Ottoman troops in Najd. However, the Ottoman troops were victorious and proceeded to invade Abu Arish. Ahmad was captured, and all his possessions in Yemen were handed back to al-Mahdi Abdallah. In spite of mutual distrust, an agreement between the imam and the Ottomans was effectuated, whereby the imam undertook to send coffee deliveries to the sultan's court. After 15 years, Tihamah was therefore once again in the hands of the Zaidi State.
The British of Bombay traded on the important seaport Mocha. In 1817 a British lieutenant was mistreated by the local population, and the British Indian authorities demanded satisfaction. The imam's governor in Mocha declined the demand, and a military action followed in 1820. After an initial setback, the British troops managed to breach the walls of Mocha and force an agreement. In the following year al-Mahdi Abdallah sent a firman to the British trading office in Mocha where he agreed to lower the duties of the port. During the 1820s, however, the British grew increasingly skeptical about their prospects in Mocha. They started to look for an alternative port, and found Aden to be an attractive alternative. Aden at this time was under the Sultanate of Lahej, thus outside of al-Mahdi Abdallah's territory. This eventually led to the British capture of Aden in 1839.
Türkçe Bilmez and Egyptian intervention
The authority of Al-Mahdi Abdallah in parts of Yemen was eroded by the appearance of a Circassian adventurer, Türkçe Bilmez. Being a soldier serving under the Egyptian viceroy Muhammad Ali Pasha in Hijaz, he mutinied and gathered discontented Ottoman militaries. The mutineers marched into the Tihamah in 1832 and captured Mocha and Hudaydah, and the land in between. He concluded an alliance with a chief of Asir, Ali bin Mukhtar, whereby they were to support each other and share the revenues of the occupied territory. Al-Mahdi Abdallah had little resources to counter the intruders. With British endorsement, Muhammad Ali sent an Egyptian force to Yemen in 1833 to deal with the chaotic situation, which was highly detrimental to trade in the region. The Asiris fell out with Türkçe Bilmez and besieged his forces in Mocha, which was blocked from the sea by the Egyptian fleet. Finally the city fell and was plundered by the Asiri tribesmen, while Türkçe Bilmez was saved on a British ship.
After these events, fighting broke out between the Egyptians and Asiris on Yemeni soil. The conflict continued for the next few years, until in 1837 Egyptian reinforcements secured the coastal cities and some of the interior. Al-Mahdi Abdallah, unable to contain the turmoil, considered giving up his country, or what remained of it, to Muhammad Ali, but this was plainly refused by his subjects. When he died in 1835, the Zaidi state was only a shadow of its former condition. Al-Mahdi Abdallah was succeeded by his son al-Mansur Ali II.