The Soviet and Communist Chinese Aid Missions established in 1958 and 1959 were the first important non-Muslim presence in North Yemen. Following the September 1962 revolution, the Yemen Arab Republic became closely allied with and heavily dependent upon Egypt. Saudi Arabia aided the royalists in their attempt to defeat the republicans and did not recognize the Yemen Arab Republic until 1970. Subsequently, Saudi Arabia provided Yemen substantial budgetary and project support. At the same time, Saudi Arabia maintained direct contact with Yemeni tribes, which sometimes strained its official relations with the Yemeni government. Hundreds of thousands of Yemenis found employment in Saudi Arabia during the late 1970s and 1980s.