The People's Democratic Republic of Yemen ( ), also referred to as South Yemen, Democratic Yemen or Yemen (Aden), was a communist state in the southern and eastern provinces of the present-day Republic of Yemen, including the island of Socotra. It united with the Yemen Arab Republic (commonly known as "North Yemen") on 22 May 1990, to form the present-day Yemen. After four years, however, South Yemen declared its secession from the north, which resulted in the north occupying south Yemen and the 1994 civil war.