Background:
North Yemen became independent of the Ottoman Empire in 1918. The
British, who had set up a protectorate area around the southern port
of Aden in the 19th century, withdrew in 1967 from what became South
Yemen. Three years later, the southern government adopted a Marxist
orientation. The massive exodus of hundreds of thousands of Yemenis
from the south to the north contributed to two decades of hostility
between the states. The two countries were formally unified as the
Republic of Yemen in 1990. A southern secessionist movement in 1994
was quickly subdued. In 2000, Saudi Arabia and Yemen agreed to a
delimitation of their border.