10 July 1991
The International Cricket Council (ICC) agreed to grant full membership to the United Cricket Board of South Africa (UCBSA), which would allow South African players to participate in test matches by the end of 1991. South Africa had ceased to be a member of the ICC after leaving the British Commonwealth in May 1961. The country had been suspended from all cricket activities in 1970, to be re-instituted as a member after the formation of a new body, the UCBSA, to oversee the administration of all cricket activities. In contrast with past practice, this body was inclusive of all cricket players in South Africa, regardless of race.
References

Wallis, F. (2000). Nuusdagboek: feite en fratse oor 1000 jaar, Kaapstad: Human & Rousseau.