The African National Congress (ANC) led the struggle that toppled apartheid in 1994 and has ruled South Africa ever since, remaining the most popular party despite a series of scandals.
Here are 10 key dates in the history of the party formed more than 100 years ago.
The South African Native National Congress was founded in 1912 in response to discrimination against blacks in the then-Union of South Africa, established two years earlier through the merger of white-run colonies and territories.
The movement changed its name to ANC in 1923.
After the white-minority National Party government institutionalised the apartheid system in 1948, the ANC organised its first mass "Defiance Campaign" in 1952.
Tens of thousands of blacks broke curfews, burned their "passbook" identity documents which were obligatory to carry, and entered whites-only areas at the risk of going to jail.
In 1959, a rebel faction created the Pan Africanist Congress (PAC).
In 1960, police opened fire on a demonstration against passbooks, killing 69 people in what became known as the Sharpeville Massacre.
In the aftermath, the government banned the PAC and ANC, which went underground.
The following year, Nelson Mandela created the ANC's military wing, Umkhonto we Sizwe (Spear of the Nation), that launched an armed struggle against apartheid.
1964: leaders jailed
Mandela, Walter Sisulu, and other ANC leaders were jailed for life in 1964 for sabotage and conspiracy.
The ANC continued to fight apartheid in exile from London, Dar es Salaam and Lusaka, and allied itself with the Soviet bloc.
1985: secret talks start
The ANC's leadership in exile held the first secret talks with apartheid officials in Zambia in 1985.
In July 1989, there was a first clandestine meeting between Mandela, still a prisoner, and hardline president P.W. Botha.
In December that year, Mandela met the new president, F.W. de Klerk.
De Klerk unbanned the ANC and other groups in 1990, also releasing Mandela and other political prisoners.
Mandela became ANC president the following year.
1994: ANC in power
The first elections open to all races were held in April 1994, with the ANC winning 62.6 percent and Mandela becoming South Africa's first black president.
Thabo Mbeki took over in 1999 but his two terms were tarnished by allegations of abuse of power and denial about the AIDS epidemic ravaging the country.
2009: first Zulu leader
The ANC compelled Mbeki to resign in 2008, before the end of his second term, amid a power struggle with party leader Jacob Zuma.
It led some ANC members to break away to form the Congress of the People (COPE) party.
The ANC won 2009 elections by 65.9 percent and Zuma became the first president from the Zulu ethnic group. Mandela and Mbeki were both Xhosa.
The party expelled radical youth leader Julius Malema in 2012 and he established the Economic Freedom Front (EFF).
2016: election setback
In its worst election result since the end of white-minority rule, the ANC took less than 54 percent of the vote at 2016 municipal polls.
It also lost an absolute majority in five of the six biggest metropolitan areas.
2018: Zuma forced out
After a nine-year presidential term marked by corruption scandals and an economic slowdown, Zuma was forced to resign by the ANC in 2018.
He was replaced by his deputy, Cyril Ramaphosa, who vowed to tackle state corruption.