(The Washington Post)

The world today mourns Nelson Mandela, who died in his South African home at age 95 after leading a historic and world-changing life. His death has sparked global celebrations of his legacy, discussions of his impact and debate over his ideology and politics. It can seem like everyone has a strongly held opinion about him.

You may find yourself, though, among the people who are generally aware of the contours of Mandela's life but may feel lost in the details of that life and what it meant for the world. It's okay – we can't all be Mandela scholars. Here, then, are the most basic answers to your most basic questions. First, a disclaimer: This is not an exhaustive or definitive account of this very important story, just some background, written so that anyone can understand it.

1. Who was Nelson Mandela?

(Chris Jackson/Getty Images)

Nelson Mandela, born in 1918, was a South African political activist who campaigned, sometimes violently, to end apartheid (more on apartheid later) starting in the 1940s. He was elected president in 1994, after apartheid was abolished, and served one term. He spent the rest of his life as an elder statesman.

Mandela's most important accomplishments were helping to end apartheid and then to help lead South Africa away from its deep racial divides and toward pluralistic democracy.

People have been arguing for decades over whether the Nelson Mandela of the 1940s, '50s and '60s is best described as a political leader, a freedom-fighter or a terrorist. Almost no one calls him a "terrorist" anymore, of course, but some people did for a long time – especially here in the United States. That Mandela got the world to embrace him and his movement is also a big part of what makes him so important.

2. What is South Africa?

South Africa is a country at the southern tip of Africa with a complicated history, one in which race has played a tremendously important role. That history goes back many centuries, of course, but we'll start in 1652.

That's the year Dutch settlers arrived, some of the earliest European colonialism in the world. These colonists have been in South Africa for so long they they developed their own language, Afrikaans, still spoken by millions of people. They became known as the "Boers," which means farmers.

The British navy didn't show up until 1795, one and a half centuries later. Almost the entire next century was a series of wars between three groups: the British government, the Dutch-descended Boers and, of course, groups from the black African majority. (To be clear, black Africans in South Africa have never been a monolithic mass but are culturally, ethnically and linguistically diverse.)

The British won those wars. Between 1902 and 1910, the Union of South Africa became a dominion of the British Empire. The British sought to cement their rule by empowering the white minority (today about a 10th of the population) over the black majority.

In 1912, black South African activists formed the African National Congress, meant to politically unify South Africans to work for greater rights and freedoms. Mandela joined the group in 1943, a 25-year-old activist, and the next year helped form the more boldly activist African National Congress Youth League.

After World War II, as the British started closing down their empire, South African whites who'd been in the country for centuries pushed for and gradually won complete independence. But they preserved their complete dominance of the country's government and institutions.

3. What was apartheid?

Apartheid, from the Afrikaans word for "apartness," was a system of laws that enforced deep racial segregation and empowered whites over other races, especially blacks. It was enacted in 1948 and lasted until 1994.

It's difficult to convey in this small a space just how awful apartheid was. Blacks, though the vast majority of South Africans, were not just barred from voting or holding office, but were denied citizenship in their own country. They were forced to live physically apart, in "homelands" and "townships," some of which resembled remote suburbs but which often appeared as vast camps or shantytowns of canvas and corrugated tin.

As black dissent against apartheid increased, the South African government responded severely and often brutally. Most infamously, in 1960, police opened fire on a demonstration in the township of Sharpeville, killing 69 people.

Through the 1960s, 1970s and 1980s, the fight over apartheid got worse and worse. Another important incident was in 1976 in the township of Soweto, when black students protested a new law requiring them to take instruction in Afrikaans. It ended with perhaps hundreds of deaths when police moved to put it down.

4. So Mandela was like Africa's Gandhi, right? He ended apartheid by organizing peaceful resistance?

No way, not at all. Mandela advocated violent resistance against the apartheid government. When people say that Mandela "fought" for equality, they mean it literally. His victory against apartheid took a very different path than Gandhi's.

In 1961, after the Sharpeville killing, a 42-year-old Mandela helped found the paramilitary arm of the ANC, called Umkhonto we Sizwe or "Spear of the Nation." The group committed sabotage against state buildings and infrastructure. He explained at his 1964 trial that peaceful efforts had failed; "only then did we decide to answer violence with violence."

Mandela was sentenced to life in prison at his 1964 trial (he'd been imprisoned since 1962 on other charges) and remained locked up until 1990, much of that in a tiny concrete cell on Robben Island, where he was forced to do hard labor. Within the prison, among other jailed ANC officials, he began to assume the role of a leader; outside the prison, he became an increasingly visible symbol of the anti-apartheid movement. That movement itself was becoming increasingly violent, particularly the militants of Umkhonto we Sizwe.

In the 1980s, Mandela held a number of negotiations with leaders of the apartheid government over resolving the decades-old conflict. In 1985, the government offered him a presidential pardon if he renounced violence; he refused. In 1989, F.W. de Klerk took office with the goal of ending apartheid. Mandela was freed in 1990. Apartheid was ended in 1991. In 1994, South Africa held its first-ever elections in which the black majority could vote. Mandela became president.

5. Can we take a quick music break?

South Africa has a wonderful music scene, and an entire mini-sub-genre dedicated to the anti-apartheid movement. It's pretty much impossible to choose just one song, but let's go with this performance of the 1987 song "Bring Him Back Home" by the South African trumpeter and singer Hugh Maskela. A number of the lyrics are in Xhosa, the native language of Mandela's ethnic group.

You can also check out this great 1999 video of Mandela himself, then 81 years old, dancing on stage to a performance of a 1986 song by Johnny Clegg calling for his release from prison.

6. What made Mandela so important? Ending apartheid, right?

Mandela's role in toppling apartheid was an enormous, historic achievement. But it was what he did after winning that battle that made him such a hero, not just to black South Africans but to the world.

Mandela was always clear that he didn't want to end apartheid just because it was horrible and racist, although it was, but because his ultimate goal was, as he said at his 1964 trial, "a democratic and free society in which all persons live together in harmony and with equal opportunities."

You have to understand the historical context here. The second half of the 20th century was filled with liberation movements, particularly in Africa and other regions dealing with the end of colonialism. Not many of them ended in pluralistic democracy, as South Africa's did. An awful lot of movements similar to the ANC, in other countries, turned pretty quickly into dictatorships. Or maybe the long-oppressed majority would take power, then turn around and oppress the minority that had been so cruel to them.

That was the norm. Mandela broke it by fighting not just for the liberation of blacks but, once he became president, for real pluralism and democracy. He left office after one term to help ensure that future leaders would feel pressure not to stay on long, as many African presidents do. He wasn't just bringing his ideals to South Africa, but proving to the world that liberation movements, present and future, really could be all that they promised.

He was the exceptionally and perhaps uniquely rare liberator who followed through on the hardest part: extending liberation to his former oppressors as well as to the oppressed. That is why Mandela is such an important model for the world.

7. Wow, he really was amazing. Did the United States help him?

You wish. South Africa's conflict was a deeply divisive global political issue. See if you can guess which two countries were often on the wrong side of it. Yes, that's right: the United Kingdom and the United States.

In the 1960s, the U.S. did oppose apartheid, and supported arms embargoes against the South African government. But the Cold War changed that.

South Africa was staunchly anti-communist and an ally against the Soviet Union. The Soviets helped back the African National Congress. Starting in the 1970s, the U.S. and U.K. supported the apartheid government. Then-president Ronald Reagan called it "essential to the free world." His administration officially designated Mandela and the ANC as terrorists. British Prime Minister Margaret Thatcher dismissed the ANC as "a typical terrorist organization."

Much of the rest of the world opposed the apartheid government, though, and many countries imposed economic sanctions and other restrictions. The issue became highly controversial within the U.S. and U.K. in the mid- and late-1980s as anti-apartheid movements gained strength there. Eventually, South Africa's two most important allies also turned against it. This helped make apartheid a burden on South Africa's whites as well, which helped bring about its end.

8. What was the thing with rugby? I remember a movie about that.

When people talk about what made Mandela such a great president, they sometimes point to his support for the country's national rugby team, the Springboks.

The Springboks were mostly white and, like lots of South African teams, had been banned from international competition as punishment for apartheid. They had been highly popular among white South Africans.

You have to understand that the apartheid government had worked very hard to create deep racial divisions in South African society. That kind of thing just doesn't change overnight. But Mandela came into office knowing that a national racial reconciliation would be crucial for the country's future. Whites and blacks, after all that had passed between them, would have to accept one another as equals and fellow citizens.

One way Mandela did this was by turning to the Springboks, this culturally white South African institution, and holding them up as something that all South Africans should be proud of. He went to games, wore the team jersey and urged black South Africans to support them. It was a way of signaling black acceptance of the former white oppressors as new equals; it was also a way of turning something that had long been associated with white South Africa  and making it simply South African, an identity without race.

9. I skipped to the bottom. Did Mandela succeed in building a free, equal, post-racial South Africa?

He made truly remarkable strides, given that he left office in 1999, less than a decade after apartheid ended. But his dream has not been fully realized: South Africa today still suffers from significant racial divisions that leave whites better off than other races, particularly the black majority. Those racial divides often blur into socioeconomic divisions.

Vast townships of corrugated tin still stretch out from Cape Town and Johannesburg. Nearly a quarter of South Africans live at or below the poverty line. The ANC, which has held power since 1994, is troubled by corruption charges. Racial resentments persist on all sides. In August 2012, police opened fire on striking workers at a platinum mine, killing 34 in an incident that for many South Africans exposed the country's still-wide divisions. More quietly, the cosmopolitan city of Cape Town can still feel divided along racial lines, though now by cultural and economic rather than legal forces.

Still, Mandela was only one person. He did not leave a perfect South Africa behind, but he helped usher it through changes that left tremendous lessons for it and the world.