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My first experience of fieldwork in Southeast Asia found me in Roi et province of Northeast Thailand. It was a total accident that led me to this spot. The mighty Mekong River was then in the early stages of being seriously affected by the construction of hydro dams on its tributaries. One of these, the Lam Dom Noi, was located within a few kilometres of the border with Laos. The area to be inundated was in my archaeological sights. But, in January 1970, a huge American airbase there was being used to bomb Vietnam, and it was regularly targeted from over the border. The Thai authorities banned me from what they euphemistically described as a ‘sensitive area’. Instead, we moved well inland, to Roi et. There, the Governor could not have been more helpful. He arranged for his motorcade to incorporate our ancient vehicle, and we drove to where, he told me, there was a promising area for my investigations. It was my first experience of rural Thailand and, after passing through several villages, we arrived at our destination, an extensive swamp that, because it was the dry season, had little standing water. The swamp was surrounded by villagers toiling away doing something that I didn’t comprehend on the high banks that flanked the flat.
I alighted to find that the ground was thick with broken potsherds. Then the Governor took us to a nearby village, arranged a house, cooks, and our basic needs, and left us to our own devices. My small team spent the next few days walking over the unfamiliar landscape, identifying potential places to dig. I chose one on the fringes of the seasonally dry swamp, where the ground was littered with thick potsherds. The second site was a mound south of the swamp, and the third lay within what I later learned were prehistoric banks and moats surrounding a prehistoric site so extensive that today it encloses five villages.
As we worked, I could hardly fail to notice the swarm of villagers labouring on and next to the swamp. As the sun burnt into the soil, so the briny water evaporated to leave a layer of white salt. They were transporting this to the edge of the flat, to fill hollowed tree trunks fitted at the base with a tap and a tube. They then filled the trunks with water that concentrated the brine before it was piped into a large metal tray over a fire-pit. As the brine evaporated, a thick layer of salt crystallised.
As we dug down, so we came across pits filled with charcoal, ash, and large, rather crudely manufactured potsherds. We went deeper and deeper, finally reaching the natural substrate about 7m down. There was no doubt that these were salt-working sites, and our radiocarbon dates went back at least 2,000 years into the Iron Age.
White gold
Salt is a vital commodity in Northeast Thailand, because it is used to ferment and preserve the wet-season abundance of fish. In November, the monsoon rains give way to six dry months. Lakes and streams shrink or disappear. After combining the wet-season fish with salt and rice in storage jars, the fish ferment, which provides abundant food for the rest of the year. Surplus salt is traded widely, and villages that own salt deposits are always wealthy.
Thirty years after that first experience, my team and I returned to Northeast Thailand for more fieldwork, this time 180km to the west in the vicinity of Phimai. This is a remarkable town, for it covers the rectangular walls and central temples of ancient Vimayapura, a major regional centre of the Angkorian empire that was linked by a royal road to the capital. And every day, as we drove out to our excavations, we passed a huge, modern salt factory, for Phimai is renowned for its salt deposits. We have now excavated several more of these Iron Age moated sites, and once again, during the early dry season, we observed the villagers hard at work extracting salt. By accumulating the salty soil into their work stations, they create mounded industrial sites. Paul Rivett, one of my graduate students, spent weeks recording and mapping the numerous steep-sided mounds that cluster round the Iron Age moated town sites, and ended up with more than 70. And when we were excavating at Ban Non Wat and Non Ban Jak, we came across salt-processing pits within each settlement. One large piece of industrial pottery still contained a thick coating of salt.
Suffice it to say that, during the Iron Age, which began about 450 BC in our region, salt was being produced on an industrial scale. It is not easy to trace possible trade routes for a perishable substance like salt, but there are lessons to be learned by casting the net wide and looking at salt-production in other parts of the prehistoric world. The other day, for example, son Tom sent us some pictures of a weekend he had spent at Hallstatt in Austria. This site featured prominently in my undergraduate studies, as its name is given to the European early Iron Age. Hallstatt was a major source of salt. It was mined by digging shafts and galleries, and the conditions were ideal for the preservation of organic material, including a backpack and a pair of shoes. During the 19th century, at least a thousand graves were excavated there, and Bettina Glunz-Hüsken has recently re-examined what has survived, and identified numerous imported grave offerings, ranging from textiles to bronze bowls and fine jewellery. Such is the wealth of these that she suggests that social elites were able to enrich themselves on the basis of the salt trade. Nor is this the only example of the control of salt to engineer social prominence.
As is often the case, reading on such comparative situations stimulates another look at information coming from my own excavations. We have found that about 2,000 years ago, the monsoon rains so vital for the rice harvest weakened, and there were generations of relative aridity. This set in train a crisis familiar to the modern ear: climate change. We have woven together a series of inputs as a means of understanding what then happened. First, we have dated the construction of the canals, banks, and what we call moat/reservoirs round the Iron Age towns, and found that they coincided with the onset of aridity. We undertook flotation to recover plant remains, finding that there was a sudden rise in the dominance of weeds that flourish in permanently wet fields. Then we found a man interred with a heavy iron ploughshare, and the team uncovered a surface covered in the hoofprints of domestic-sized water buffaloes, suggesting that these valued traction animals were secured within the settlement when not busy hauling a ploughshare. Our bioanthropologists chimed in with demographics: there was a surge in infant deaths ascribed to the spread of malarial mosquitoes in the wet rice-fields, and the many diseases associated with fish and shellfish if not properly cooked. Finally, there is evidence from the human burials. Some men and women were interred in discrete groups with rituals that included clay-lined coffins in which the dead lay wearing an impressive array of exotic ornaments. A man wore bronze belts, 150 bangles, and gold and silver discs in his ear lobes. A woman’s necklace was made of gold and agate beads. There were iron spears, knives, and sickles, along with very finely made ceramic vessels that contained fish skeletons. Before the coffin was closed, the corpse was covered in rice.
We have suggested that these elite leaders profited by owning the land improved by irrigation and ploughing to produce rice surpluses, for rice to this day is synonymous with wealth. But now we also have to factor the importance of salt into the exchange relationships that brought the gold, silver, carnelian, agate, and bronze to these wealthy communities. Moreover, one cannot ignore the sequel to the rise of those Iron Age aggrandisers. Within a few generations of that agricultural revolution, the first indigenous states were forming. We have the names of early kings, their palace centres, and religious temples and rituals adopted from their contact with South Asian entrepreneurs and brahmans. Devānīka, meaning celestial protection, was one of these rulers, a king who in the 5th century AD founded the city of Wat Phu near that now-abandoned American airbase. Many of these early states were gathered up into one kingdom by Jayavarman II, the founding king of Angkor, in about AD 800. Angkor lay on the bank of the Great Lake, the greatest fishery in Southeast Asia, while Vimayapura was then the prime source of salt. So it was that salt travelled down that royal road, generating the wealth that led another Jayavarman, the Prince of Vimayapura, to seize power and found the Angkorian Dynasty of Mahidharapura in about 1080.
Charles Higham is a Professor at Otago University in New Zealand, and an authority on Cambodia's Angkor civilisation and Ban Non Wat in Thailand.
