Out of Africa The money trail ... anthropologist Ian McIntosh. How did medieval coins from East Africa end up on a remote island off the Northern Territory? It's a mystery that may rewrite Australia's early history. There is a slender island off Australia's northern coast, a place of taboo and old grief, where the wind blows hard and crocodiles swim in the warm sea. An island of sharp rock and pale sand, of paperbark swamps and swarming green ants, deserted now but still home to the sacred places of the Yolngu Aboriginal people of north-east Arnhem Land who once lived there. The walls of their hidden caves are vivid with red and yellow drawings of ships and strangers, of sails and guns, archives of a crowded history. It is a lonely island, 11 rough hours' sailing from the mainland, where 69 years ago a young serviceman from Sydney walked along the beach and felt something small and hard underfoot. In the sand were four worn coins, nearby, five more. He picked them up, put them in a tobacco tin and took them home. Then he forgot about them. Morry sat on these coins for 30 years. What else are Australians sitting on? Many years after Morry Isenberg arrived home from Marchinbar Island, where he was part of a RAAF radar unit during World War II, he remembered that tin. He had the coins valued, was assured they were worthless and, disappointed, donated them to a museum, where they disappeared into storage again. But before he handed them over, four of the nine were identified as 17th- and 18th-century Dutch coins. Similar coins had been found in Australia before. The other five, though, were far stranger - coins minted up to 1000 years ago in a fabled medieval city state on a remote East African island. Only two others have ever been found outside East Africa. And yet somehow, inexplicably, here were five of them, scattered on an empty beach thousands of kilometres away across the Indian Ocean. Coin of destiny ... one of the copper alloy coins from East Africa's Kilwa Kisiwani sultanate that were found on Marchinbar Island. Photo: Sue Stafford, courtesy of the Powerhouse Museum The conundrum of how coins from the island sultanate of Kilwa Kisiwani, off the coast of modern-day Tanzania, could possibly journey to the island of Marchinbar, off the coast of the Northern Territory, captivates and confounds everyone who hears of them. Australian anthropologist Ian McIntosh has been trying to explore Marchinbar ever since he first learnt of the coins almost 30 years ago. In July, armed with Isenberg's original map, the 56-year-old finally succeeded, leading the first expedition to Marchinbar, where he and six others combed the island feverishly for a week. Though they didn't find any ancient coins, the team returned with a haul of intriguing shipwreck debris, along with news of rock art depicting numerous different types of ships. It's still unclear whether the Kilwa and Dutch coins arrived on the island together, perhaps carried as a sailor's precious talisman lost at sea or given as trinkets to Yolngu by seafarers. Some speculate, more explosively, that the Kilwa coins arrived much earlier, and hint at far earlier contact with Australia, perhaps pre-dating the official European discovery of Australia 400 years ago. "A Kilwa coin in Kilwa is not worth much," says McIntosh. But a Kilwa coin in Arnhem Land is priceless for what it might tell us about our past. Search team ... Ian McIntosh (at right) with Marchinbar traditional owner Terry Yumbulul and Yumbulul's wife Clely in Nhulunbuy, just before the expedition departed for Marchinbar in July. Photo: courtesy of Ian McIntosh Lying in the vast Arafura Sea like a crocodile stretching in the sun, the Wessel Island chain, with the island of Marchinbar at its northern tip, stretches for 120 kilometres off the coast of northeastern Arnhem Land. With perilous cliffs on its east coast sloping down to long, sandy beaches on its west, Marchinbar's profound isolation is guarded by rips and reefs. Monsoonal winds and frequent cyclones scour the landscape, which, until the 1800s, was home to Yolngu clans before smallpox arrived, killing almost everyone. Those who survived fled, leaving behind their sacred places. For decades it was a place of taboo, though a few families returned in the early 1990s when an outstation, since destroyed by a cyclone, was built. For the Yolngu, Marchinbar remains a place of old sorrow. For the soldiers of the RAAF's 312 Radar Unit, who arrived as World War II raged, it was a very good place to watch for Japanese planes. The creek the Yolngu call Djinjan winds through the sand on Marchinbar to mingle with the salt water. The beach is wild and empty. Years later, Isenberg, who died in 1991, would write in his notes that he was out fishing when he felt something with his foot. He picked it up between his toes - his son Norman guesses he had his hands full of fishing gear - and saw it was a coin. He found several others on the sand, about a metre below the high-water mark, and scrabbled in the sand to find still more. The five African coins he found are about the size of a dollar coin and very thin, their edges nibbled by time. Their worn surfaces record the names of sultans and have pious, rhyming inscriptions flowing from front to back - "Ali son of al-Hasan trusts in the Master of Bounties" reads one in translation. Made of lowly copper, they would most likely have been small change on Kilwa, where they still wash up on the beaches, says Adelaide-based archaeologist and East African coinage specialist John Perkins. Treasure map ... a World War II map of Marchinbar. The coins are a mix of ages, likely to date from the late 11th century up to 1340, depending on which sultan they were minted for, says Perkins, and were never intended for foreign trade or travel. Only two others have been found elsewhere, in Oman and Zimbabwe. Notes Perkins, "To find coins which do not travel in one of the most remote places on Earth? You couldn't make that up. Having reached the sands of Marchinbar, the serendipity of winding up at Morry Isenberg's feet is breathtaking. Coins don't rest on sand for long; they sink. What if he hadn't gone fishing that day? "A day later," says one of McIntosh's team, geomorphologist Tim Stone, "and they wouldn't have been there." In the 12th and 13th centuries, Kilwa was the greatest of all the East African coastal trading centres. Lying just off Tanzania, the Islamic island city-state had a ringside seat on the edge of the Indian Ocean, that mighty thoroughfare bustling with traders, slavers and explorers. Links to the past ... ruins of a palace on the island of Kilwa, an African trading power in the 12th and 13th centuries. Photo: John Perkins Following a route that linked the Swahili coast with Arabia, Persia, India, Malacca in modern-day Malaysia and the cherished cloves and nutmeg from the Spice Islands of modern-day Indonesia, travellers rode the feisty seasonal monsoon winds to buy the gold and ivory the Kilwans sourced from the African mainland. From its reefs, the builders of Kilwa cut live coral to fashion into their city's grandest buildings, its brilliant white glittering over the noisy marketplaces. But in 1505 the Portuguese sacked the city, and the ruins of bright Kilwa now crumble silently above the empty harbour. Morry Isenberg never went to Africa, and he almost didn't make it to Marchinbar, either. His son Norman recalls that his father was rejected when he first tried to enlist because, as a sheet-metal worker, he was considered more valuable at home. But my father was a stubborn chap, and for three weeks he stopped going to work, only turning up on pay day, waiting to get sacked. He eventually did get sacked, and the next day he joined the air force. After the war, Isenberg returned to Sydney, where he ran a lawnmower repair and sales shop in Bondi, got married and raised a family. It wasn't until the late 1970s, when he began selling off some of his coin collection, that he decided to find out more about his Marchinbar find. He got in touch with Bill Mira, a Sydney coin enthusiast who quickly identified the four Dutch East India Company coins, but had no idea what the others were. He passed them to a fellow collector whose contacts at the British Museum pinpointed their origin and age. Discovery ... the late Morry Isenberg during the war. Isenberg then took them to a valuer but was told they were worthless and in 1983, he donated his find to what's now known as the Powerhouse Museum in Sydney. Mira was intrigued enough to write about them for an Australian coin magazine, speculating that they could have come from an ancient shipwreck. His theory sparked a ripple of interest, which quickly ebbed away. Another decade went by. And then he contacted Ian McIntosh. To an outsider, it seems astounding that it has taken until now for anyone to search for more clues. And yet the Wessels is no casual destination - expensive and logistically difficult to get to, it's also Yolngu land, and entry by outsiders is tightly controlled. Without old connections between McIntosh and Wessels traditional owner Terry Yumbulul, it's unlikely the expedition would have happened. Beginning as a teacher and linguist on nearby Elcho Island in 1986, McIntosh worked with the Yolngu for many years on sea rights and reconciliation; wrote a biography of one of their greatest leaders, the late David Burrumarra; and was adopted into a Yolngu clan. McIntosh heard of the coins when he was on Elcho, and he and Burrumarra tried then to raise funds for an expedition. When Bill Mira contacted him in the 1990s, McIntosh tried again, without success, to find funding. Since then, McIntosh's focus on reconciliation has taken him to projects around the world - in Rwanda, Gaza and Kenya. But wherever he's travelled, he's carried with him a tiny colour picture, clipped long ago from a travel magazine, of the ruins of Kilwa. Now the photo is stuck on his study wall at the University of Indiana-Purdue University Indianapolis, where he is professor of anthropology. McIntosh still writes academic papers on Arnhem Land and travels there whenever he can. Last year, he flew to Canberra to give a talk on Macassans, the fishermen from what is modern-day Indonesia, who headed to Arnhem Land in their hundreds every year from the 1780s to the early 1900s, hunting trepang, or sea cucumber, and coming ashore to process their catch. Afterwards, historian Campbell Macknight, who has spent 50 years documenting Macassan-Aboriginal contact, sought him out. Recalls McIntosh: " 'I enjoyed your paper,' Macknight told me, 'but have you ever thought about those African coins and how they got there?' " The comment stayed with McIntosh, and back in the US, he wrote a journal article outlining his theory that the coins may have been lost on Marchinbar by a shipwrecked Indonesian sailor known to have lived with the Yolngu in the 1800s. He then began trying again to raise funds for an expedition, and this time found it, from a jumble of sources - among others, a Swiss foundation working for indigenous rights, the Australian Geographic Society, and his mother. At the same time, he and Darwin heritage consultant Mike Owen established Past Masters, an international network of like-minded specialists fascinated by the currents of Indian Ocean history, among them archaeologists, numismatists, indigenous leaders and heritage consultants. Suddenly, there was momentum. At this time of the year, as the south-east winds rage, waves pound Marchinbar's cliffs and people on the mainland put away their boats. "When I heard they wanted to go in July, I asked, do they really?" says Kim Wilkinson, skipper of Nhulunbuy-based SS Charters, who took the team on the nauseatingly rough journey to Marchinbar. With them they took the map annotated by Isenberg 30 years ago, the crucial spot marked by a small cross inside a circle. They slept on board to avoid crocodiles and spent long days scrub-bashing through vines and thickets. "We took off in all directions, just following our instincts," says Tim Stone. Every afternoon we came back sunburnt, scratched and dehydrated, and every morning we just wanted to get out there again. Despite their hours of searching, the metal detectors turned up just one coin: a 15-year-old specimen from Uruguay. Even knowing how much the endless wrestle between wind, waves and sand would have changed the beach since Isenberg was there, Adelaide numismatist Peter Lane was disappointed. We knew it would be a needle-in-a-haystack kind of job - but we all believed there were probably other coins Morry didn't find. Marchinbar had its consolations. Through painstaking footwork, and despite cyclones having removed almost every trace of the wartime camps, the team managed to verify each element of Isenberg's map - meaning they could pinpoint where the coins had been found. Among the washed-up plastic bottles and fishing nets and more than 300 discarded bullet shells, they also found a range of possible shipwreck artefacts, including a large handcrafted piece of wood traditionally used to support decks. And in rock shelters and caves - some of them described by Terry Yumbulul and others found by the team themselves - they were thrilled to find beautiful collections of rock art. The team now is trying to identify exactly what the Yolngu of old saw on the waves and depicted in the art: at least a dozen different types of sailing vessels, whales being hunted and people with hats and guns. "That is what our ancestors were standing there looking at," says traditional owner Yumbulul. Did the ships come to the island by choice - for fresh water, turtle or wood - or by accident, trapped by one of its many reefs? Likely the arc of the Wessels chain acted "like [cricketer Adam] Gilchrist's extended arm," as Mike Owen puts it, catching ships blown off course in the mercurial Arafura Sea. And where there was that much sea traffic, shipwrecks are likely - perhaps one of which could explain the secret of the coins. Lane is one who thinks the two sets of coins were probably lost together. "They were found together in a very small area," he says. The chances of that happening from two separate deposits is pretty challenging to the mind. But geomorphologist Stone, also an archaeologist, sees no reason why the coins could not have been deposited on the ocean floor hundreds of years apart but washed up together. After all, he points out, shells of different ages do it all the time. What's more, he thinks it entirely possible that the Kilwa coins arrived before the Dutch officially discovered the Wessels in 1623. Kilwan traders, famed for their navigational skills, are known to have reached Malacca in the 1500s - could they have come even further? "If there are Kilwa coins there from 1000 years ago, the simplest explanation to me is that there were Kilwans there 1000 years ago," says Stone. To me, that makes much more sense than somebody carrying them together and losing them in one spot - and then Morry finding them. I think that's even more far-fetched. Archaeologist Paul Donnelly, the Powerhouse Museum's curator in charge of its coin collection, agrees that even if the coins came from different wrecks, prevailing currents could have swept them ashore roughly at the same spot. "It's a motley collection of token coins," he says, "yet it could be implying some totally unknown connection with Australia - some unrecorded and unprecedented connection with our country's history." For past masters like Ian McIntosh, solving the Kilwa coins mystery is inseparable from their mission to reinvigorate Australian history. They're critical of the well-trodden narrative of Australia's discovery, dominated by Dutch navigators and James Cook, for obscuring how much was happening long before Europeans arrived. McIntosh argues that for thousands of years, Arnhem Land has been at the forefront of human contact, with wave after wave of people reaching its coastline. "The idea we were sitting out there, isolated in the Southern Ocean, waiting for European eyes to liberate us from our seclusion - it's complete nonsense," he says. The coins might have come with one of the trepang fishermen; when explorer Matthew Flinders anchored at Marchinbar in 1803 to collect fresh water, he saw the wreck of one of their vessels, a proa, on the sand. But Yolngu oral history records many other, earlier arrivals. Stories of Yolngu forebears, often represented by the fearless and curious dingo, befriending some visitors and attacking others, tell of encounters between the dingo and whale-hunters, of intermarriages and alliances, of mysterious pre-Macassan visitors they call Bayini. Yumbulul emphasises the history of amicable contact in the islands, such as when Yolngu helped Flinders' crew who came ashore: "If they worked together, hand in hand, back then, why not now? That is the message from the Wessels. Yolngu stories of the Wessels also speak of visits by strangers wearing "mirror," evocative of men in armour. Could Marchinbar have something to say in the old debate about the chances of a "secret" Portuguese discovery of Australia before the Dutch claimed the honour in 1606? The Portuguese were in both Timor and Malacca in the 1500s, and had a direct link to Kilwa. "I have no doubt that the Portuguese were well aware of the northern Australian coast," says McIntosh. News of the expedition has prompted dozens of people to contact Past Masters with details of their own finds - some of which McIntosh is keen to investigate. He wants to see the British Museum's popular Portable Antiquities Scheme, under which people voluntarily share details of their amateur finds on a public register, adopted here to help fill in the gaps of our history. "Morry sat on these coins for 30 years," says McIntosh. In the 1980s, he travelled to Queensland as a government warden inspecting archaeological sites, often visiting private properties where "station owners would show me the most extraordinary collections of Aboriginal artefacts that they had in their sheds. Some were better than I had seen in any museum. The potential for historic amateur finds is perfectly illustrated by Darwin teenager Christopher Doukas, who, in 2010, saw what he thought was the metal end of a fire hose poking out of the mud on Dundee Beach, a fishing hamlet south-west of Darwin. What he and his family dug out was a metal cannon of unknown age or origin, though they found pictures of similar-looking 500-year-old Portuguese swivel guns online. Past Masters members are now testing sediment stored inside the gun's barrel in an effort to date it. "People say there was a helmet or there was another gun at Dundee, but where are they now?" asks McIntosh. People find things, then put them in their sheds. And not just in sheds - the Past Masters network is also hoping to examine a cannon, found in the sea off Darwin a century ago and now in the South Australian Maritime Museum, which has never been fully identified. McIntosh sees a great chance to broaden the study of Australian history in classrooms around the country. What child wouldn't love the story of a soldier finding ancient coins from a far-off land, or of cannons buried in the mud? He's begun working with Elcho Island elders to ensure children there learn more of the history all around them. The Yolngu here were a part not only of Asia, but of the Indian Ocean and beyond. They want to know. Meanwhile, the team is hoping crowd-funding will get them back to Marchinbar next year with the University of Indiana's Office of Underwater Science, veteran explorers of several Spanish treasure wrecks in the Caribbean, to widen the search. Involving the Yolngu is paramount; the next expedition will include traditional owners who can interpret rock art, and workshops are planned to train young Aboriginal rangers as frontline detectives in identifying coastal archaeological finds. Like the others, Tim Stone is itching to get back. A small excavation of the floor of a rock art site is high on his wish-list. The potential for archaeological research in the coastal area of northern Australia is mind-boggling. Morry Isenberg would sometimes tell his son Norman of his time on the Wessels as a place steeped in wildness. He walked alongside the sea one day before noticing a dark shape in the shallow water keeping pace with him - a giant ray, which darted away when he threw a grenade at it. His son also loved the story of Morry arriving at the makeshift mess hut and abruptly shooting his rifle over a superior's head - killing a giant snake that had quietly draped itself over the rafters above. The story of the coins he told less often, yet it has proved a tale like no other. The coins are still in the Powerhouse Museum's high-security storage basement, each in their own protective envelope. Though they can be seen on the museum's website, they haven't been on display since 1990, when they were oddities in a larger exhibition on Australia's coin history. The fact they have lain in storage for so long "says something unflattering about us as a nation - there is a lack of inquiry," rues Mike Owen. But not anymore; the small change of 1000 years ago could one day tell more about our country's history than a young serviceman could have dreamed when he bent to pick them up on that faraway beach so long ago.