The Mutawakkilite Kingdom of Yemen ( ), also known as the Kingdom of Yemen or simply as Yemen, or, retrospectively, as North Yemen, was a state that existed between 1918 and 1962 in the northwestern part of what is now Yemen. Its capital was Sana'a until 1948, then Taiz. From 1962 to 1970, it maintained control over portions of Yemen until its final defeat in the North Yemen Civil War. Yemen was admitted to the United Nations on 30 September 1947. History Background Zaidi religious leaders expelled forces of the Ottoman Empire from what is now northern Yemen by the middle of the 17th century but, within a century, the unity of Yemen was fractured due to the difficulty of governing Yemen's mountainous terrain. In 1849, the Ottoman Empire occupied the coastal Tihamah region to put pressure on the Zaiddiyah imam to sign a treaty recognizing Ottoman suzerainty and allowing for a small Ottoman force to be stationed in Sana'a. However, the Ottomans were slow to gain control over Yemen and never managed to eliminate all resistance from local Zaydis. In 1913, shortly before World War I, the Ottoman Empire was forced to formally cede some power to highland Zaydis. Independence On 30 October 1918, following the collapse of the Ottoman Empire, Imam Yahya Muhammad of the al-Qasimi dynasty declared northern Yemen an independent sovereign state. In 1926, Yahya proclaimed the Mutawakkilite Kingdom of Yemen, becoming both a temporal king as well as a (Zaydi) spiritual leader, and won international recognition for his new state, such as with the Kingdom of Italy, entering into the Italo-Yemeni Treaty in 1926. Consolidation In the 1920s, Yahya expanded his power to the north into Tihamah, but he collided with the rising influence of the Saudi king of Nejd and Hejaz, Abdul Aziz ibn Sa'ud. In the early 1930s, Saudi forces retook much of this territory before withdrawing from parts of the area, including the southern Tihamah city of Al Hudaydah. The present-day boundary with Saudi Arabia was established on 20 May 1934 by the Treaty of Taif, following the Saudi–Yemeni War in 1934. Yahya's non-recognition of his kingdom's southern boundary with the British Aden Protectorate (later the People's Democratic Republic of Yemen) that had been negotiated by his Ottoman predecessors resulted in occasional clashes with the British. In 1932, the governments of Yemen and the Kingdom of Iraq signed a treaty that led