In addition to the competition between the US and the USSR, several other factors motivated the involvement of international powers: the Sino-Soviet split, Third World solidarity against Western exploitation and imperialism, and in the case of the US, Angola's large oil reserves. The USSR was involved with the MPLA from its foundation in the late-1950s.  Starting in 1958, MPLA founding member Mario de Andrade would travel to Moscow on a regular basis for various conferences and meetings.