Abdullah ibn Saud (عبد الله بن سعود ) was the fourth and last leader of what later became known as the First Saudi State. He succeeded his father Saud bin Abdul Aziz bin Muhammad ibn Saud as imam of the "Muwahhideen" (or Wahhabis, as they were known to their opponents) in 1814, and ruled until 1818. While the House of Saud had many successes under Saud, they had also managed to provoke a war with the Ottoman Empire. As such, Abdullah immediately had to face an invasion of his domains by an Ottoman-Egyptian army under the command of Ibrahim Pasha, the son of the viceroy of Egypt, Muhammad Ali. The Ottoman forces began their campaign by quickly recapturing Mecca and Madinah. Heavily outnumbered and under-equipped, the Saudi forces retreated to their stronghold of Najd. Rather than engage the invaders in open battle on his own turf, however, Abdullah decided to attempt to weather the invasion by fortifying his forces in the Najdi towns. As a result, Abdullah watched Ibrahim take the villages of Najd one by one, sacking any town that resisted, until Ibrahim finally reached the Saudi capital at Diriyah. After a siege that lasted several months, Abdullah finally surrendered in the winter of 1818, marking the end of the Saudi state. Ibrahim systematically razed Diriyah to the ground and sent many members of the Al Saud clan into captivity in Egypt and Constantinople. Abdullah himself was promptly put to the sword in Constantinople at the behest of the Ottoman Sultan, and his severed head was thrown into the waters of the Bosphorus. Although the Ottomans maintained several garrisons in Najd thereafter, they were unable to prevent the resurrection of the Saudi state under another member of the Saudi clan, Turki ibn Abdallah ibn Muhammad ibn Saud.