the British and the Lower Yafai. In 1899 Sultan Bubakar bin Seif died. He was succeeded by Sultan Abdulla bin Muhsin. In 1902 the Fadhli Sultan established a new customs post at Zanzibar and levied dues on Yafai qafilahs. The Yafai retaliated by cutting off the water-supply from the Naza channel. The Fadhli then attacked Al Husn and Ar Rawa. In 1903 the Resident endeavored to effect a settlement, but the Yafai Sultan refused to attend the conference. In 1904 the Fadhli attacked Ar Rawa and Khanfar, taking possession of the latter and for a time no settlement was reached; while relations with the Lower Yafai Sultan continued strained, partly owing to his dissatisfaction with the position accorded to certain sections of the Upper Yafai, over whom he was inclined to assert a claim to general suzerainty, and partly to his dissatisfaction with the rank and precedence assigned to himself. In 1916 Sultan Abdulla bin Muhsin died. He was succeeded by his cousin, Sultan Muhsin bin Ali, who renewed friendly relations with the Aden Residency, to which he paid periodical visits. In 1925 Sultan Muhsin bin Ali died and was succeeded by his son, Sultan Aidrus bin Mubsin bin Ali. This Sultan has established his personal authority over the whole of the Lower Yafai clans. In June 1926 a truce of four years was concluded between the Lower Yafai and Fadhli Sultans. In June 1929 the Sultan of Lahej settled this long-standing feud and restored Khanfar to the Lower Yafai. In November 1925 Major M. C. Lake was sent on a special Mission to Lower and Upper Yafai. Sultan Aidrus accorded him a warm welcome and gave him every assistance in his journey. In 1926 Sultan Aidrus bin Mulisin was granted a personal salute of 9 guns. In 1931, the population of Lower Yafai was estimated at 70,000, and the gross revenue at Rs. 10,000 a year. The Lower Yafa Sultanate was a founding member of the Federation of Arab Emirates of the South in 1959 and its successor, the Federation of South Arabia, in 1963. Its last sultan, Mahmūd ibn Aidrūs Al Afīfi, was deposed and his state abolished in 1967 upon the founding of the People's Republic of South Yemen. Eventually South Yemen united with North Yemen in 1990 to form the Republic of Yemen. Geography Its capital was the former residence of the Banū Afīf Sultans. There