Yemen
Two states

Arab nationalism had an influence in some circles who opposed the lack of modernization efforts in the Mutawakkilite monarchy. This became apparent when Imam Ahmad bin Yahya died in 1962. He was succeeded by his son, but army officers attempted to seize power, sparking the North Yemen Civil War. The Hamidaddin royalists were supported by Saudi Arabia, Britain, and Jordan (mostly with weapons and financial aid, but also with small military forces), whilst the military rebels were backed by Egypt. Egypt provided the rebels with weapons and financial assistance, but also sent a large military force to participate in the fighting. Israel covertly supplied weapons to the royalists to keep the Egyptian military busy in Yemen and make Nasser less likely to initiate a conflict in the Sinai.After six years of civil war, the military rebels formed the Yemen Arab Republic.

The revolution in the north coincided with the Aden Emergency, which hastened the end of British rule in the south. On 30 November 1967, the state of South Yemen was formed, comprising Aden and the former Protectorate of South Arabia. This socialist state was later officially known as the People's Democratic Republic of Yemen and a programme of nationalisation was begun.

Relations between the two Yemeni states fluctuated between peaceful and hostile. The South was supported by the Eastern bloc. The North, however, was not able to get the same connections. In 1972, the two states fought a war. The war was resolved with a ceasefire and negotiations brokered by the Arab League, where it was declared that unification would eventually occur. In 1978, Ali Abdullah Saleh was named as president of the Yemen Arab Republic. After the war, the North complained about the South's help from foreign countries. This included Saudi Arabia.

In 1979, fresh fighting between the two states resumed and efforts were renewed to bring about unification. Thousands were killed in 1986 in the South Yemen Civil War. President Ali Nasser Muhammad fled to the north and was later sentenced to death for treason. A new government formed.
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