Around a large table in a bright room in the University of Oxford’s Pitt Rivers Museum, four members of the Maasai tribe from east Africa are inspecting a small object. It has been carefully placed in front of them by a curator wearing special handling gloves. The Maasai say that it is a bracelet, an orkatar. They talk between themselves, in the maa language, about what the bracelet is used for. “This is something that cannot be sold or given,” says Yannick Ndoinyo, a junior elder from Loliondo, northern Tanzania. The orkatar symbolises the death of a father and is a form of inheritance that passes down the generations. How did it end up in a museum in Oxford? Perhaps it was stolen from the original owner or given away under duress. According to the database, it was “donated” to the Pitt Rivers Museum in 1904 by Alfred Claud Hollis, a colonial administrator in British East Africa.

This encounter between the Pitt Rivers, one of the most important ethnological museums in the world, and the Maasai is part of a process of cultural decolonisation. The relationship began when Maasai activist Samwel Nangiria visited the museum in November last year for a conference. The Pitt Rivers has more than 300,000 objects in its collection, many of which were “acquired” by colonial functionaries, missionaries and anthropologists in the heyday of the British empire. The museum itself is curated in a peculiar style – in line with the request of benefactor Augustus Pitt Rivers – with objects organised according to type rather than place of origin. This Victorian aesthetic has been consciously upheld: the Pitt Rivers is often referred to as a “museum of a museum”. There are shrunken heads from the Amazon and rudimentary tools from India; a magisterial totem pole from the Haida nation in Canada towers above the central, darkened atrium.

Nangiria walked through the museum and stopped when he saw something he was not expecting: his own culture, entombed in a glass cabinet. “When I saw objects from the Maasai community I was a little bit shocked,” he tells me. “[They were] poorly described, with a lack of what the object is meant for [and its] cultural significance.” His heart started beating so fast that it felt like it was vibrating: “Because I know our culture is not dead. It’s a living culture.”

Facebook Twitter Pinterest Diplomacy … Samwell Nangiria, second right, and fellow Maasai Kuweya Timan Mollel and Scholastica Ene Kukutia explain an object’s significance to curators. Photograph: John Cairns

Nangiria, a purposeful and diplomatic presence, expressed his displeasure to the museum’s director, Laura Van Broekhoven. She sent him a copy of the museum’s strategic plan for the future and invited him back. Keenly aware of its problematic origins, the Pitt Rivers, like many museums, engages “originating communities” – in the museum-world lingo – to allow them to reclaim the narrative around their objects. Last month, Nangiria, with four other Maasai from Tanzania and Kenya, and help from the Oxford-based NGO InsightShare, returned to do so.

Curators take great care when holding arrows, assuming their tips are poisoned. Francis, a village elder, confirms this: 'If it mixes with your blood then you have five minutes left'

One purpose of the weeklong visit was to provide the museum with more accurate information. The database was littered with errors and gaps: it transpires that an object marked as a Maasai bracelet is actually an anklet; a trinket made for an unknown purpose in fact plays a vital role in circumcision rituals. After a Maasai sword is laid down on the table, Marina de Alarcón, joint head of collections, tells us that the museum takes great care when holding arrows, assuming that their tips – as is Maasai custom – are poisoned. Francis Shomet Ole Naingisa, a village elder, duly confirms this: “If the poison mixes with your blood then you have five minutes left.”

Of the 60 objects examined, the Maasai came across five that are sacred, which “they would not expect to find elsewhere apart from within their community”. One was the orkatar. Another was an isurutia, a necklace used as a wedding dowry. Nangiria sent a photograph to village elders back home via WhatsApp: “They were astonished to hear that such a thing was here,” he tells me. “They say this particular object might have brought bad omens to the family [who lost possession of it].” For the Maasai, these items are not historical curiosities. They are part of a living culture.

Facebook Twitter Pinterest ‘You have our soul’ … Hoa Hakananai’a, the Easter Island moai in London’s British Museum. Photograph: Paul Quayle/Alamy Stock Photo

The relationship between European museums and the people from whom their collections were taken has never been more fraught. The same week as the Maasai visit, Tarita Alarcón Rapu, governor of Easter Island, begged for the return of the Hoa Hakananai’a statue from the British Museum in a tearful message that went viral: “You, the British people, have our soul.”

A few days later came the publication of a report commissioned by President Emmanuel Macron, who had expressed his desire to see colonial-era items in France returned to Africa. Macron has his own reasons for this type of cultural diplomacy: it eases the passage of further economic and military cooperation with Francophone Africa. Nonetheless, the report is bold, recommending that France return African treasures if governments request them.

Museums handle the question of repatriation as delicately as their objects. The Museums Association’s policy statement notes that it is a “complex issue involving a range of emotional, ethical, legal and political factors”. In my interviews I heard suspicion from some in the museum world about the politicised nature of state-to-state transactions, while the legal framework governing returns can be ambiguous, as has been with the case with recovering art stolen during the second world war. The British Museum has agreed to hold talks about Hoa Hakananai’a, but a likely conclusion will be a temporary return on loan, as was the case with Nigeria’s Benin bronzes.

Repatriation, however, is not the only form of decolonisation. For the activist Alice Procter, who gives unofficial tours of London museums that foreground their histories of colonialism and slavery, just as urgent is transforming the institution itself. “Decolonisation means rethinking the structure of the museum,” she tells me. “Until people from [originating] communities are actually working in museums with their collections on a permanent and long-term basis, it won’t be truly institutional change.”

Facebook Twitter Pinterest Exchange … the Maasai visitors take in Oxford’s sights. (l-r) Samwel Nangiria, Francis Shomet Ole Naingisa, Kuweya Timan Mollel, Yannick Ndoinyo and Scholastica Ene Kukutia. Photograph: John Cairns

Procter tells me that the Pitt Rivers is a good example of a museum working hard to “rethink the role, power and status of museums”, and Van Broekhoven is refreshingly forthright. Fluent in the language of decolonial studies, she admits that the model of originating communities visiting for a week to talk about their customs is not sufficient and that the power dynamic between participants should always be carefully considered. “There are times [in these exchanges] when you think, ‘What are we doing here? Are we decolonising or are we neo-colonising?’” she says. “But that’s why it’s so important to think through the power balances in these relationships. It should certainly never be tokenistic. Decolonising really needs to be a process and as it deeply questions the institutional practices it will often be painful.”

Will the Maasai be able to facilitate the return of sacred objects? Van Broekhoven tells me over email that “in principle”, and provided they find funding, the museum is ready to “learn together how we might envision new ways of redress”. The words are carefully chosen. Nangiria, ever the diplomat, suggests an alternative solution in one of our conversations: inviting elders to perform a spiritual ceremony that will “disconnect” the objects from their cultural function, allowing the Maasai to actively donate them to the museum. The museum will wait to hear from the elders to “jointly decide” on the next steps in the partnership.

Facebook Twitter Pinterest Learning together … the collection is inspected. Photograph: John Cairns

At a public event on the final day of their visit, the five Maasai, led by Scholastica Ene Kukutia, a women’s rights activist from Kenya, perform a ritual in the museum. Standing on the balcony overseeing the collection, sporting red shukas and bejewelled with earrings and necklaces that chime as they move, the group sing a melodious incantation that speaks of a meeting between “great cultures”. Attendees cry, as does Nangiria. He thanks the museum for “opening its doors” to them.

But history always finds a way to seep through to the present, especially in a city like Oxford. The day before, I joined the Maasai at the university’s Weston Library. Enduring the November cold, they posed for a photograph on a balcony that frames the city’s skyline: implacable limestone that speaks of centuries of imperial wealth. Inside, they were shown archival maps of Maasai territory. The British engineered a forced migration, at gunpoint, of the Maasai at the turn of the century, moving them from one of the most fertile plains of Kenya to a drier part of Tanzania. Nangiria pores over the maps to see the changing contours of his people’s land.

One book taken from the library’s archives, written in 1901 by Sidney Langford Hinde, a medical officer in British East Africa, is called The Last of the Masai. It is a work of colonial anthropology. Kukutia is intrigued and reads from a chapter: “All Masai [sic] are quick at learning and, since they are both quiet and intelligent, they make excellent servants.” She laughs. And then, after reading a few more lines, lets out a sound of weariness. I ask if she is glad that she came to Oxford. She says yes. She is happy that they have provided the Pitt Rivers Museum with better information for people learning about her culture. What’s more: “Now they have made us at least aware of where our belongings are.”

• This article was amended on 5 December 2018. An earlier version referred to the Haida community. This has been changed to nation.