Yemeni unification

Yemeni unification took place on May 22, 1990, when the area of the People's Democratic Republic of Yemen (also known as South Yemen) was united with the Yemen Arab Republic (also known as North Yemen), forming the Republic of Yemen (known as simply Yemen).

Unlike East and West Germany, Communist and Nationalist China, North and South Korea, or North and South Vietnam, the two Yemens were not formed by a civil war or occupation. North Yemen became a state after the collapse of the Ottoman Empire in November 1918, whereas South Yemen at that time had been a British colony; a South Yemeni insurgency led by two nationalist parties revolted, causing the United Kingdom to withdraw from its former colony.

Following the North Yemen Civil War, the north established a republican government that included tribal representatives. It enjoyed modest oil revenues and remittances from its citizens working in the oil-rich Arab states of the Persian Gulf. Its population in the 1980s was estimated at 12 million as opposed to 3 million in South Yemen.

South Yemen developed as a Marxist, mostly secular society ruled first by the National Liberation Front, which later morphed into the ruling Yemen Socialist Party. The only avowedly Marxist nation in the Middle East, South Yemen received significant foreign aid and other assistance from the USSR.

In October 1972, fighting erupted between north and south; North Yemen was supplied by Saudi Arabia while South Yemen was supplied by the USSR. Fighting was short-lived and the conflict led to the October 28, 1972 Cairo Agreement, which set forth a plan to unify the two countries.

...
Wikipedia