My parents’ home, in Umujieze, Nigeria, stands on a hilly plot that has been in our family for more than a hundred years. Traditionally, the Igbo people bury their dead among the living, and the ideal resting place for a man and his wives is on the premises of their home. My grandfather Erasmus, the first black manager of a Bata shoe factory in Aba, is buried under what is now the visitors’ living room. My grandmother Helen, who helped establish a local church, is buried near the study. My umbilical cord is buried on the grounds, as are those of my four siblings. My eldest brother, Nnamdi, was born while my parents were studying in England, in the early nineteen-seventies; my father, Chukwuma, preserved the dried umbilical cord and, eighteen months later, brought it home to bury it by the front gate. Down the hill, near the river, in an area now overrun by bush, is the grave of my most celebrated ancestor: my great-grandfather Nwaubani Ogogo Oriaku. Nwaubani Ogogo was a slave trader who gained power and wealth by selling other Africans across the Atlantic. “He was a renowned trader,” my father told me proudly. “He dealt in palm produce and human beings.”

Long before Europeans arrived, Igbos enslaved other Igbos as punishment for crimes, for the payment of debts, and as prisoners of war. The practice differed from slavery in the Americas: slaves were permitted to move freely in their communities and to own property, but they were also sometimes sacrificed in religious ceremonies or buried alive with their masters to serve them in the next life. When the transatlantic trade began, in the fifteenth century, the demand for slaves spiked. Igbo traders began kidnapping people from distant villages. Sometimes a family would sell off a disgraced relative, a practice that Ijoma Okoro, a professor of Igbo history at the University of Nigeria, Nsukka, likens to the shipping of British convicts to the penal colonies in Australia: “People would say, ‘Let them go. I don’t want to see them again.’ ” Between the fifteenth and nineteenth centuries, nearly one and a half million Igbo slaves were sent across the Middle Passage.

My great-grandfather was given the nickname Nwaubani, which means “from the Bonny port region,” because he had the bright skin and healthy appearance associated at the time with people who lived near the coast and had access to rich foreign foods. (This became our family name.) In the late nineteenth century, he carried a slave-trading license from the Royal Niger Company, an English corporation that ruled southern Nigeria. His agents captured slaves across the region and passed them to middlemen, who brought them to the ports of Bonny and Calabar and sold them to white merchants. Slavery had already been abolished in the United States and the United Kingdom, but his slaves were legally shipped to Cuba and Brazil. To win his favor, local leaders gave him their daughters in marriage. (By his death, he had dozens of wives.) His influence drew the attention of colonial officials, who appointed him chief of Umujieze and several other towns. He presided over court cases and set up churches and schools. He built a guesthouse on the land where my parents’ home now stands, and hosted British dignitaries. To inform him of their impending arrival and verify their identities, guests sent him envelopes containing locks of their Caucasian hair.

Funeral rites for a distinguished Igbo man traditionally include the slaying of livestock—usually as many cows as his family can afford. Nwaubani Ogogo was so esteemed that, when he died, a leopard was killed, and six slaves were buried alive with him. My family inherited his canvas shoes, which he wore at a time when few Nigerians owned footwear, and the chains of his slaves, which were so heavy that, as a child, my father could hardly lift them. Throughout my upbringing, my relatives gleefully recounted Nwaubani Ogogo’s exploits. When I was about eight, my father took me to see the row of ugba trees where Nwaubani Ogogo kept his slaves chained up. In the nineteen-sixties, a family friend who taught history at a university in the U.K. saw Nwaubani Ogogo’s name mentioned in a textbook about the slave trade. Even my cousins who lived abroad learned that we had made it into the history books.

Last year, I travelled from Abuja, where I live, to Umujieze for my parents’ forty-sixth wedding anniversary. My father is the oldest man in his generation and the head of our extended family. One morning, a man arrived at our gate from a distant Anglican church that was celebrating its centenary. Its records showed that Nwaubani Ogogo had given an armed escort to the first missionaries in the region—a trio known as the Cookey brothers—to insure their safety. The man invited my father to receive an award for Nwaubani Ogogo’s work spreading the gospel. After the man left, my father sat in his favorite armchair, among a group of his grandchildren, and told stories about Nwaubani Ogogo.

“Are you not ashamed of what he did?” I asked.

“I can never be ashamed of him,” he said, irritated. “Why should I be? His business was legitimate at the time. He was respected by everyone around.” My father is a lawyer and a human-rights activist who has spent much of his life challenging government abuses in southeast Nigeria. He sometimes had to flee our home to avoid being arrested. But his pride in his family was unwavering. “Not everyone could summon the courage to be a slave trader,” he said. “You had to have some boldness in you.”

My father succeeded in transmitting to me not just Nwaubani Ogogo’s stories but also pride in his life. During my school days, if a friend asked the meaning of my surname, I gave her a narrative instead of a translation. But, in the past decade, I’ve felt a growing sense of unease. African intellectuals tend to blame the West for the slave trade, but I knew that white traders couldn’t have loaded their ships without help from Africans like my great-grandfather. I read arguments for paying reparations to the descendants of American slaves and wondered whether someone might soon expect my family to contribute. Other members of my generation felt similarly unsettled. My cousin Chidi, who grew up in England, was twelve years old when he visited Nigeria and asked our uncle the meaning of our surname. He was shocked to learn our family’s history, and has been reluctant to share it with his British friends. My cousin Chioma, a doctor in Lagos, told me that she feels anguished when she watches movies about slavery. “I cry and cry and ask God to forgive our ancestors,” she said.

The British tried to end slavery among the Igbo in the early nineteen-hundreds, though the practice persisted into the nineteen-forties. In the early years of abolition, by British recommendation, masters adopted their freed slaves into their extended families. One of the slaves who joined my family was Nwaokonkwo, a convicted murderer from another village who chose slavery as an alternative to capital punishment and eventually became Nwaubani Ogogo’s most trusted manservant. In the nineteen-forties, after my great-grandfather was long dead, Nwaokonkwo was accused of attempting to poison his heir, Igbokwe, in order to steal a plot of land. My family sentenced him to banishment from the village. When he heard the verdict, he ran down the hill, flung himself on Nwaubani Ogogo’s grave, and wept, saying that my family had once given him refuge and was now casting him out. Eventually, my ancestors allowed him to remain, but instructed all their freed slaves to drop our surname and choose new names. “If they had been behaving better, they would have been accepted,” my father said.

The descendants of freed slaves in southern Nigeria, called ohu, still face significant stigma. Igbo culture forbids them from marrying freeborn people, and denies them traditional leadership titles such as Eze and Ozo. (The osu, an untouchable caste descended from slaves who served at shrines, face even more severe persecution.) My father considers the ohu in our family a thorn in our side, constantly in opposition to our decisions. In the nineteen-eighties, during a land dispute with another family, two ohu families testified against us in court. “They hate us,” my father said. “No matter how much money they have, they still have a slave mentality.” My friend Ugo, whose family had a similar disagreement with its ohu members, told me, “The dissension is coming from all these people with borrowed blood.”

I first became aware of the ohu when I attended boarding school in Owerri. I was interested to discover that another new student’s family came from Umujieze, though she told me that they hardly ever visited home. It seemed, from our conversations, that we might be related—not an unusual discovery in a large family, but exciting nonetheless. When my parents came to visit, I told them about the girl. My father quietly informed me that we were not blood relatives. She was ohu, the granddaughter of Nwaokonkwo.

I’m not sure if this revelation meant much to me at the time. The girl and I remained friendly, though we rarely spoke again about our family. But, in 2000, another friend, named Ugonna, was forbidden from marrying a man she had dated for years because her family found out that he was osu. Afterward, an osu friend named Nonye told me that growing up knowing that her ancestors were slaves was “sort of like having the bogeyman around.” Recently, I spoke to Nwannennaya, a thirty-nine-year-old ohu member of my family. “The way you people behave is as if we are inferior,” she said. Her parents kept their ohu ancestry secret from her until she was seventeen. Although our families were neighbors, she and I rarely interacted. “There was a day you saw me and asked me why I was bleaching my skin,” she said. “I was very happy because you spoke to me. I went to my mother and told her. You and I are sisters. That is how sisters are supposed to behave.”