On a sunny morning in November, 2018, twelve men and two women gathered in a lavishly furnished living room in Oguta, a town in southeastern Nigeria, with the air-conditioning at full blast. They had come to discuss the caste system that persists among the Igbo people in the region. The group’s host, Ignatius Uchechukwu Okororie, a short, sixty-two-year-old retired civil servant, split open a kola nut with his fingernails and ate its flesh; he then passed a metal tray of nuts around the room, for the others to taste. “He who brings kola nut brings life,” he said. The breaking of kola nut, known as iwa oji, is an important Igbo ritual traditionally performed to welcome guests to a gathering. The group in Okororie’s living room were members of a caste called ohu: descendants of slaves who, almost a century ago, were owned by townspeople. They are typically restricted from presiding over such ceremonies. In Okororie’s house, the iwa oji was a small rebellion.

Slavery existed among the Igbo long before colonization, but it accelerated in the sixteenth century, when the transatlantic trade began and demand for slaves increased. Under slavery, Igbo society was divided into three main categories: diala, ohu, and osu. The diala were the freeborn, and enjoyed full status as members of the human race. The ohu were taken as captives from distant communities or else enslaved in payment of debts or as punishment for crimes; the diala kept them as domestic servants, sold them to white merchants, and occasionally sacrificed them in religious ceremonies or buried them alive at their masters’ funerals. (A popular Igbo proverb goes, “A slave who looks on while a fellow-slave is tied up and thrown into the grave should realize that it could also be his turn someday.”) The osu were slaves owned by traditional deities. A diala who wanted a blessing, such as a male child, or who was trying to avoid tribulation, such as a poor harvest or an epidemic, could give a slave or a family member to a shrine as an offering; a criminal could also seek refuge from punishment by offering himself to a deity. This person then became osu, and lived near the shrine, tending to its grounds and rarely mingling with the larger community. “He was a person dedicated to a god, a thing set apart—a taboo forever, and his children after him,” Chinua Achebe wrote of the osu in “Things Fall Apart.” (The ume, a fourth caste, was comprised of the slaves who were dedicated to the most vicious deities.)

In the nineteenth century, the abolition of slavery in the West inadvertently led to a glut of slaves in the Igbo markets, causing the number of ohu and osu to skyrocket. “Those families which were really rich competed with one another in the number of slaves each killed for its dead or used to placate the gods,” Adiele Afigbo, an Igbo historian, wrote in “The Abolition of the Slave Trade in Southeastern Nigeria, 1885–1950.” The British formally abolished slavery in Nigeria in the early twentieth century, and finally eradicated it in the late nineteen-forties, but the descendants of slaves—who are also called ohu and osu—retained the stigma of their ancestors. They are often forbidden from speaking during community meetings and are not allowed to intermarry with the freeborn. In Oguta, they can’t take traditional titles, such as Ogbuagu, which is conferred upon the most accomplished men, and they can’t join the Oriri Nzere, an important social organization.

Westerners trying to understand the Igbo system often reach for its similarities with the oppression of black Americans. This analogy is helpful but imperfect. Igbo discrimination is not based on race, and there are no visual markers to differentiate slave descendants from freeborn. Instead, it trades on cultural beliefs about lineage and spirituality. The ohu were originally brought to their towns from distant villages. Community ties are very important in Igbo culture, and so, while the descendants of, say, American immigrants are encouraged to assimilate, the ohu have never lost their outsider status. With the osu, the diala originally believed that mixing with a deity’s slaves would earn them divine punishment. (In its spiritual aspect, the plight of the osu is similar to that of dalits in India or of burakumin in Japan, whose ancestors are believed to have done “polluting” work as butchers or tanners, and who are therefore thought to be impure.) With Christianization, the conscious aspect of this belief dissipated, but not without leaving traces. “The fear people have is: before long, our children and children’s children will be bastardized,” Okoro Ijoma, a professor of Igbo history at the University of Nigeria, Nsukka, told me. “It is about keeping their lineage pure.”

Perhaps the most important difference is that, though abolition in the West was preceded by centuries of activism that slowly (and imperfectly) changed popular attitudes, abolition in southeastern Nigeria was accomplished by colonial fiat—and only after the British no longer had an economic stake in the trade. It therefore seemed to many diala as arbitrary and self-serving as when the British pushed the Igbo, in the nineteenth century, to abandon subsistence farming in favor of cultivating cash crops, such as palm oil. The institution of slavery ended, but the underlying prejudices remained. In 1956, the legislature in southeastern Nigeria passed a statute outlawing the caste system, which then simply went underground. “Legal proscriptions are not enough to abolish certain primordial customs,” Anthony Obinna, a Catholic archbishop who advocates for the end of the system, told me. “You need more grassroots engagement.”

No data exists on the number of slave descendants in southeastern Nigeria today; it is rarely studied, and the stigma often compels people to keep silent about their status. (Ugo Nwokeji, a professor at Berkeley who studies the issue, estimates that five to ten per cent of Igbos, which would mean millions of people in Nigeria, are osu, and likely an equivalent number are ohu.) Recently, slave descendants have begun agitating for equality, staging protests, and pressuring politicians. In 2017, the governor of Enugu State spoke out against the discrimination, saying that it violated the country’s constitution. In Oguta, ohu have distributed pamphlets and sued diala family members who tried to block them from receiving what they considered to be their inheritances, including access to communal farm land. Two years ago, when an elderly ohu man was snubbed for a seat on the village council, the ohu held a parallel ceremony to install him in the position. The ceremony was invaded by diala, who caused a brawl that the police had to break up. “Their population is much higher than ours,” Okororie said. “That is our only handicap.”

The ohu in Okororie’s living room were there to meet with Ogechukwu Maduagwu, the founder of the Initiative for the Eradication of Traditional and Cultural Stigmatisation in Our Society, or Ifetacsious. “It’s a divine calling,” Maduagwu, who is diala, told me. “We are not blaming or judging our ancestors as evil, but we must accept our new world of freedom and equality.” Maduagwu is forty-three, with thick braids held up in a pompadour. Since August, she had been travelling to each of the five Igbo states to sit down with slave descendants and traditional rulers for “reorientation and reconciliation” meetings. In Nigeria, traditional rulers (such as Igwes and Ezes) form a parallel system of government; though they have no formal role in the state, they have considerable political and economic influence, and preside over aspects of traditional culture, including matters of caste. Maduagwu was hoping to convince the rulers to abolish the system in their regions, a strategy she thought would be more effective than legislation. “It is the responsibility of the traditional rulers and their people to come together and say, ‘We don’t want to continue with this,’ ” she said.

She urged the ohu to avoid violent protest, which she felt was counterproductive. “I plead and implore everyone to rid his heart of vengeance,” she said. At the mention of reconciliation, several ohu smiled skeptically, and, when she finished, almost everyone raised his hand to comment. Afam Oririeze, a retired teacher, pointed out the difficulty of changing not just policy but people’s beliefs. “What is important is us being accepted as human beings,” he said. Okororie commended Maduagwu’s vision but expressed doubt about how much of an impact she could have. “The situation in Oguta is so bad that children in primary schools know and talk about who is ohu and who is not,” he said. “Can you imagine that even children as young as five years old see me and call me ohu?”

The stigmas of the Igbo caste system exist all over southeastern Nigeria, but they are especially salient within small rural communities, where a family’s lineage is impossible to hide. Joseph Agbo, a fifty-two-year-old philosophy professor, grew up in the outermost ward of the eight or nine wards that make up the town of Isi Enu. Everyone in the ward, which is called Isi Enu-Isi, is ohu; their ancestors, being slaves, were allocated the territory on the town’s outskirts, so that they would bear the brunt of raids from neighboring villages. Growing up, Agbo was often ridiculed by other children. “When we go to the disco, or when we go to fetch water in the stream, they’ll just call you ohu, and there will be fights,” he told me. “We would fight at the stream, fight at the disco hall. . . . It was a battle all year round.”

A year before Agbo was born, his village held a funeral for one of its oldest men. Traditionally, when a respected man in Isi Enu dies, the townspeople honor him by playing an igede—a percussion instrument made from wood and animal skin. The people of Isi Enu-Isi made an igede for the man’s funeral, which infuriated their neighbors, who felt that the ohu could never be distinguished enough to deserve the instrument’s music. On the day of the funeral, men from the other four villages stormed Isi Enu-Isi, destroyed the igede, and razed the buildings and farms. Agbo’s father, a soldier, was away on duty when his village was destroyed. When he returned home after his service—emboldened by his battlefield experience and by the possession of a gun—he made another igede and kept armed watch as another ohu man played it on the hill. This was the first act of open defiance in the community. In the nineteen-eighties, Agbo’s aunt, Margaret Nnaji, got a grant to set up a vocational center in Isi Enu, where women could learn skills like hairdressing and tailoring. Townspeople protested that a major municipal project shouldn’t be spearheaded by an ohu. “They started one propaganda, saying, ‘How can the heel go ahead of the toes?’ ” Agbo told me. Officials shut down the center and took away its equipment.

Agbo was the first ohu from his town to marry a diala woman. In 2016, on the fiftieth anniversary of the attack on Isi Enu-Isi, he campaigned, unsuccessfully, for the other four villages to issue an apology. Agbo typically responds with humor when people call him a slave, asking them to show him their proof of purchase. “If you go to buy a car, before you leave the place, you should come out with a receipt,” he told me, laughing. “If anyone says they bought me, that I’m a slave, I am not disputing it—just produce a receipt.” He went on a popular radio show with a friend, a traditional ruler from another community, to raise awareness of his campaign, and was alarmed by the responses from listeners. “People were calling and abusing us, and saying that we were going against Igbo culture and tradition,” he said. “I shuddered.”

One of the main complaints among the ohu in Isi Enu is that they have no representatives on the town’s council of elders. Some towns have set up separate municipalities where the ohu have their own governments. In 2016, violence broke out in Alor Uno, a village in Enugu State, when descendants of the local deity’s slaves (known as ugbene, instead of osu) took to the streets, demanding their own autonomous community; protests turned into riots, and a young man died in the chaos. Aloysius Agbo, an Anglican bishop who worked to end the crisis (and who is unrelated to Joseph Agbo), supported the osu, but worried that segregation would only reinforce the enmity. “If they did that, the division would be there eternally,” he told me. Last year, Joseph Agbo wrote a petition to have ohu included on his town’s council, the result of which is still pending. “Sometimes, ohu take issues to court, and you can tell that the judge is a supporter of the discrimination, so the case ends up being ‘Come today, come tomorrow’—it drags on for so long that you grow tired or run out of money, then withdraw,” Agbo said. “If you ask them, they may not admit that it is the ohu thing. But we know.”

Maduagwu, the founder of Ifetacsious, was not always conscious of caste discrimination. She grew up in a diala family in Oguta; her father worked in a health center and her mother traded goods in the market. As a child, she observed that a woman who lived on a farm belonging to the family, and whom she called Auntie Maria, always spoke meekly with her parents and brought gifts of fresh fruit and vegetables whenever she visited. Her mother told her that it was because of Maria’s caste. “Her father bought Auntie Maria’s father, and so both the father and daughter are ohu,” Maduagwu told me. She learned that her family had owned slaves for generations; in the early twentieth century, her paternal great-great-grandfather had murdered his most prosperous slave and her children, fearing that they would outshine his children and someday take over leadership of the family. “The freeborn people always discussed them behind their backs, and referred to them as ‘bushmeat,’ ” Maduagwu said. Her mother warned her that she was “not allowed to date or marry any of them, because it was forbidden.”

Two years ago, Maduagwu was working as a makeup artist in Lagos. A friend of hers had been engaged for two years; then her friend’s family found out that her fiancé was osu, and forced her to break it off. This friend spent two weeks in Maduagwu’s apartment, inconsolable. Maduagwu decided she would work to end the caste system. “The humanity and activism in me came alive,” she said. She started sending out group messages on WhatsApp, urging people to stop discriminating. She argued that the taboo of mixing with the osu had already been breached. “Today, we are tenants in their houses. We are on their payroll. We go to borrow money from them. You walk into a restaurant and you eat and you don’t know who made the food,” she said, in a video that she posted on YouTube. “Since we all have broken the rules and there was no disaster, it means that the gods are innocent and we are ignorant.” She received threatening messages from other Igbos; one told her that if she set foot in his village she wouldn’t go home alive. “I told them that I understand, because I was once in their position,” she said.

In April, 2017, she started Ifetacsious, which now has ten workers and meets in Lagos. Getting funding has been difficult: most international aid groups are aware of discrimination based on race, gender, or sexuality, but the situation among the Igbo is hard to explain. One of Maduagwu’s goals is to end the taboo of intermarriage, which will prove challenging. Anthony Obinna, a Catholic archbishop in the city of Owerri, first officiated a mixed wedding—between a diala man and an osu woman, without the consent of their parents—a decade ago, and has handled about eleven more in the years since. “Families usually don’t attend,” he told me. “Only friends and well-wishers.” He is currently facing a lawsuit from the family of a mixed couple that he married in 2017. “In some ways it is even worse than the black-white divide in America,” he told me. “We speak the same language, eat the same food. There is no facial or cultural difference—but this is happening.”

Maduagwu also hopes to convince traditional governments to include ohu. “It is not possible,” Dennis Nnamani, who works in the cabinet of the Igwe, or traditional ruler, in Apaugo, told me. “This is not a question of fundamental human rights.” Two years ago, Apaugo’s Igwe died, and, since then, the community has been searching for a new ruler. Candidates usually make their interest known through their families; a kingmakers’ committee, composed of members of the Igwe’s cabinet, chooses finalists, and the state governor makes the final selection. In 2017, some ohu put their names forward for the position. But Nnamani believes that, because the ohu came to the community as slaves, and therefore were not originally from the town, it would be inappropriate to select one as the Igwe. He likened it to choosing a recent immigrant to the U.K. as the next King of England. “Those who settled much later . . . they don’t have the right to ask for certain positions,” he said.

Maduagwu has gained the support of the Obi of Onitsha, the head of the council of traditional rulers in Anambra State. After meeting with Maduagwu in October, he said publicly that he believed it was time to abolish the caste system in Igboland. A local newspaper erroneously reported that the Obi was “abolishing” the caste system, and the news went viral. In December, a Nollywood actor, collaborating with a traditional ruler in Nri, organized a ceremony to abolish the system, during which a few osu shook hands with the traditional leaders present. The event was widely publicized on social media. Activists worry that this might create an impression that the issue is resolved. “It’s not a Facebook thing,” Jedidiah Onuoha, a member of Ifetacsious, told me. “It requires hard work, engaging communities one by one, not accumulating likes. . . . There won’t be any instant results.”

For slave descendants who live in Nigeria’s cosmopolitan centers, or who grew up abroad, the stigma is not a daily reality, but it can arise unexpectedly. In November, I visited Ogadinma, a former government official who is in her seventies, at her mansion in one of Nigeria’s major cities. (Ogadinma asked to be identified by one of her middle names, to shield her family from caste stigma.) Her house is decorated with photographs of her with dignitaries from around the world. Ogadinma’s father, who was osu, grew up in a small village near Owerri. His brilliance in school earned him a scholarship to the University of London. When he returned to his village, in 1949, the townspeople composed songs to welcome him, despite his caste. “They respected him because of his success, his education,” Ogadinma told me. He held prominent positions in the regional government. “We lived in a big house, with stewards, cooks,” she added, “so there was no room to feel inferior to anybody. At all.”

Centuries ago, Ogadinma’s great-great-great-grandmother fell out with her brothers, stormed out of their home in anger, and took refuge with osu in another village, becoming one of them. One of Ogadinma’s sisters was believed to have been the reincarnation of that great-great-great-grandmother, and, each time she threw a tantrum, their mother warned her to be careful of her temper, which had, in her past life, led the family to become osu. It wasn’t until the issue came up in preparations for family weddings that Ogadinma realized the importance of this bit of family lore. Before a marriage takes place, Igbo families embark on iju ajuju, or “asking questions,” during which they send emissaries to investigate whether the families are related, or whether one has a history of mental illness that would jeopardize the lineage. Ogadinma was one of more than twenty children in her family’s home, and she saw some of her siblings’ marriage prospects ruined because of their caste. “That’s when I became conscious of osu,” she said. In 1970, she avoided this fate by marrying a successful businessman who is also osu.

Ogadinma followed her father into a career in public service, holding several appointed positions. In 2007, she ran for political office, and petitions poured in from local politicians arguing that she was “not suitable” for election. They didn’t say why, but it was obvious to Ogadinma, and she lost the primaries. “When people want to have an edge over you, they rake up those issues,” she said. During a meeting of key members of a national political party, in 2016, she got into an argument with a senator, and he brought up her osu status. “He said that, under normal circumstances, he wouldn’t have any business with me,” Ogadinma said. “I told him that his grandparents would not have been able to get jobs as servants in my father’s house, even if they had applied, because they were uneducated.”

Charity Obilor, a fifty-eight-year-old osu businesswoman, was outraged by some of the remarks that she heard each time an osu campaigned for elections. In 2007, she co-founded a regional osu association, called Nneji—or “people from the same womb”—which now has more than three thousand members. The group has lawyers who represent osu in court cases about caste discrimination, and it whips up support for osu running for political office. In 2004, Obilor was elected to local government in Owerri. Members also encourage romantic relationships between their children, and Obilor is aware of several such marriages that have taken place. “That’s my specialty, and, so far, I haven’t received any disappointment,” she told me.

Two days after meeting with the ohu in Oguta, Maduagwu returned to meet with the town’s Eze. He sat in a large parlor, before a tray of broken kola nuts and half-empty glasses of alcohol, surrounded by the Okpara—the oldest men from Oguta’s twenty-seven villages. Local custom forbids a woman from standing in the presence of the Eze in his parlor, so Maduagwu sat to address her audience. She argued that it was unfitting, in the modern world, to judge people by their birth, and urged the rulers not to feel bound by tradition. “Men sat down to make these rules,” she said.

“We can also sit down and remake the rules.” One by one, the Okpara stood to respond. They seemed baffled by the recent agitation among the ohu. They felt that they had always welcomed them, and considered it a betrayal; one compared the situation to unknowingly cuddling a bomb. “There has never been any difference between us and the ohu in Oguta,” Samuel Uzoma, the chairman of the Okpara, said. “We treat them like brothers and sisters. They eat with us, we drink from the same water, our children mix—we do everything together.” One man, who appeared younger than the rest, stood up to express his sympathy for Maduagwu’s cause. “We may have been living in peace with the ohu, but there was always something that they were being deprived of,” he said. “They bottled up their bitterness, and it has exploded.” The men agreed to hold meetings with the ohu to discuss possible changes they could make—a partial victory. “You don’t pull out a bad tooth with great force. Otherwise, blood will spill everywhere,” Uzoma said. “You tug at it slowly, slowly, until it finally comes out.”

Later that week, Maduagwu attended a meeting with eight of the twelve Igwes of Ogbaru, a nearby town. The Igwes sat in grand armchairs and dressed in traditional Igbo dress—loose tops patterned with the head of a lion, ankle-length cloth tied at the waist, and coral beads around the neck. Again, she laid out her case. Afterward, the men told her in a mix of English and Igbo that they had deliberated and agreed that it was time to abolish the ohu caste in their domains. (There are no osu in Ogbaru.) They would meet with the ohu and the families that had owned slaves to work out the more contentious details of the transition. They proposed, for example, that the ohu pay a token sum to the families that bought their ancestors, to symbolically buy back their freedom. (There is a grim precedent for such a payment: in 1833, when slavery was abolished in the British colonies, the Crown paid the equivalent of more than sixteen billion pounds to former slaveholders, as reparation for their lost property.) In this case, the diala would likely donate the money they receive to the church. Some ohu are keen for anything that would bring an end to the discrimination, but others feel that it would be ridiculous for them to pay for something—equality—that should be rightfully theirs. “Nobody owns me,” Okororie, who hosted the meeting of ohu in Oguta, in November, told me. “How can I pay money to people who don’t accept me?”

Maduagwu thought that it made sense to use the same principle of exchange that led to the ohu’s enslavement to “rewind the process.” “Money changed hands when the slaves were bought,” she said. “Money also needs to change hands for abolition to take place.” This kind of transaction is important in local custom. She likened it to the fact that, when an Igbo couple gets married, the bride’s family receives a “bride price” from the groom’s family—in money or gifts—and, if the marriage ends, they must refund it before she can remarry. (Until then, any children resulting from a new union are considered to belong to the previous husband.) After the slave payment changes hands, the diala families would publicly apologize on behalf of their ancestors, and the ohu would accept the apology. Then the head of each slave-owning family would strike his ofo—a staff that represents authority—and declare the ohu free. The Igwes would write a joint declaration abolishing the caste system in their town, and, Maduagwu suggested, announce “a curse on anyone who will afterwards practice it at any level.” This would be followed by a celebratory feast. The Igwes hoped to accomplish all of this within a year.

There were still hundreds of towns across southeastern Nigeria to visit, but Maduagwu was excited about the Igwes’ decision. “No traditional ruler has the power to impose on another,” she said. “It has to be done community by community.” She had begun to imagine a future in which the result in Ogbaru was replicated across the region. “It’s going to be a homecoming and historic event, whereby the chairmen of the traditional rulers’ council of the five southeastern states, with the approval of all other traditional rulers of the five southeastern states, will come together and abolish osu, ohu, ume, and diala,” she said. “All the other traditional rulers will simultaneously abolish it in their communities, and there will be merriment and celebration all over Igboland. How glorious that will be!”