An ancient story etched in Chinese folklore since the beginning of civilisation as we know it may finally be decoded following a 'mindblowing' discovery in the historic city of Xi'an.
For nearly 2,000 years, the myth of Prince Gao - son to the brutal first emperor of China, Qin Shi Huang - has been carried down the generations, carved into legend in the surviving epic saga of historian Sima Qian, himself writing around 85 BCE.
Now, the discovery of a 16-tonne coffin in an expansive burial chamber near the mausoleum of Qin Shi Huang and his terracotta warriors could bring the myth to life.
Experts believe the tomb may belong to the forgotten prince, and the treasures inside could help piece together fragments of an ancient story of how one of the world's first states rose and fell.
Fifty years since the discovery of the famed terracotta warriors, built in their hundreds to protect the Qin strongman in the afterlife, British-Chinese filmmakers have received unprecedented access to explore the ongoing work to excavate the chamber.
Here, they learn of the ongoing race to carefully uncover and preserve record of our collective history before it is lost to time and exposure.
At the bottom of a tomb in central China, 16 metres deep and 109 metres long, a coffin sealed for millennia continues to puzzle archaeologists.
The scale of the site is enormous, and its significance has stirred sentiments that experts may soon uncover verifiable evidence to support a myth until now handed down through ancient texts.
'Every time I go down I still feel amazed,' said dig leader Jiang Wenxiao, as reported by The Times.
The tomb was discovered a little over a decade ago, but has come into focus with the anticipated Netflix documentary Mysteries of the Terracotta Warriors.
In a tiny enclave of central China, the famous warriors and the tomb together straddle the colossal resting place of China's first emperor, Qin Shi Huang.
What is the Shiji
The Shiji, known in English as the Records of the Grand Historian, is no ordinary history book.
It took Sima Qian 18 years to compile more than 520,000 words, covering individual biographies and major events over a period spanning 2,000 years.
For comparison, a fairly standard 300-page book might expect to cover around 80,000 words.
From the Shiji, written around 86 BCE, we still have rare insight into the lives of people living some 4,000 years ago.
As China began its Bronze Age in the 2nd millennium BCE, Stonehenge was being completed, woolly mammoths went extinct and horses were first tamed and used for transport.
Sima Qian's work provides a valuable historical record of events. But it also gives us insight into the beliefs and interests of the time - trust in the 'divine right' of rulers, revolt and revolution, the lives of the rich and the powerful, opinions on slavery, gambling, reactions to foreign peoples, and the justifications of war.
The Qin Dynasty
Started by Sima Tan, Great Scribe of the Han Dynasty, in the late 2nd century BCE and completed by his son around 86 BCE, the Shiji paints an impressively detailed picture of life in Qin China.
As well as stories of individuals, it provides a sense of the geography of the Dynasty and how Qin Shi Huang consolidated power in by overcoming its rivals.
While much of the historical record of the Warring States period was destroyed after unification, the Shiji gives some account of the origins of the Qin Dynasty and the shape of the state's ruling lineage.
Accuracy
Sima Qian cites numerous contemporary witnesses in his history of events. This includes, at times, sources that appear to contradict each other.
However, he writes in the Shiji that he had only written down as history that which he knew to be true 'and in doubtful cases left a blank'.
The reliability of the work has been questioned, predominantly as Qian would not have had access to reliable sources dating 2,000 years before his own time.
Still, the archeological record has so far tended to prove Sima Qian right. Sima recorded a list of thirty or so Shang rulers in his history, predating him by some 1,600 years. Inscriptions on genuine bones uncovered in the modern era listed the same names - lending some credence to his work.
It took more than 7,000 workers to construct the 22sq-metre mausoleum over a period of 38 years. Their craftmanship is evidenced by the lasting preservation of their work.
But within a year of the mausoleum's completion in 208 BCE, Qin Shi Huang died and the great Qin Dynasty fell into bitter civil war. The capital was destroyed and the citizens of the empire ultimately divided between 18 separate kingdoms.
Today, we still turn to myths passed down through the generations to get a sense of life in the ancient world. Soon after the collapse of the Qin Dynasty, early historians began keeping records of fantastical tales of great leaders, dramatic battles and local legends.
The myth of Prince Gao, the son of China's merciless first emperor, was written into history by the great storyteller Sima Qian, a product of the imperial Han Dynasty that followed the early Qin Dynasty.
From Sima Qian's monumental history, the Shiji, the early Chinese learned about the short-lived Qin Dynasty - and carried the story of an isolated prince requesting his own death as his empire fell into disarray.
It was a complicated period in Chinese history, the bringing together of early states after centuries of bloodshed between warring factions emerging and being toppled by tribes quicker to evolve.
After conquering all of his rivals to unify China, Qin Shi Huang briefly sat atop the pile, presiding over a vast empire with an iron fist and carving out the first tentative shapes of what Chinese administration could look like.
Among his most notable achievements was the Great Wall of China, connecting walls built from the 7th century BCE into a powerful border protecting the empire from nomadic invaders.
Qin had four princes ready to succeed him - Prince Gao, Prince Fusu, Prince Huhai and Prince Jianglu - but the dynasty would collapse immediately after his death.
After just 14 years, the fledgling state was thrown into a devastating civil war brought on by heavy resistance from forgotten classes.
Prince Huhai, the youngest, took up the mantle upon his father's death and purged the courts of his siblings.
According to the legend - one of very few surviving to the modern day - Prince Gao wanted desperately to flee the new terror, but feared as much the repercussions his family would have to endure.
So the story goes, Gao said he regretted not following his father into the afterlife and asked to die and be buried in the necropolis built for his father.
Seizing a straightforward solution to his problem, the rising Prince Huhai accepted the deal, even offering 100,000 bronze coins for his burial.
The mausoleum, due 21 miles (35km) northeast of Xi'an - the former eastern edge of the historic Silk Roads - was built more than two millennia ago in 246BCE.
Owing to its scale and the care with which it was built, it survives today with thousands of terracotta statues still preserved in hundreds of nearby pits.
When archaeologists uncovered the tomb of the emperor, they feared it could still be filled with boobytraps designed to deter unwanted visitors. Sima Qian claimed the mausoleum was 'filled with rare artefacts and wonderful treasure'. To protect this, he wrote, 'craftsmen were ordered to make crossbows and arrows primed to shoot at anyone who enters the tomb'.
'Mercury was used to simulate the hundred rivers, the Yangtze and Yellow River, and the great sea, and set to flow mechanically,' he went on.
'Above were representations of the heavenly constellations, bellow, the features of the land. Candles were made from the fat of "man fish", which is calculated to burn and not extinguish for a long time.'
Today, tourists still travel to the city to see the lifelike statues of fierce warriors, horses, chariots and weapons - a rare insight into the lives and priorities of those living millennia ago.
The preservation of such relics has helped historians gather huge detail on the life of China's first emperor, with many books being written about his transformation of a region embroiled in warfare into the semblance of a modern state.
His legacy is the creation of the bureaucratic and administrative structures still seen in China today, even beyond attempts to intentionally unsettle and displace the order of old.
As American political scientist Francis Fukuyama framed it, the period saw the transformation of China for a series of tribes into modern states complete with organised armies, mechanisms for tax collection and new philosophies on the purpose and reach of government.
The historical record provides not only a window into the ancient world, then, but context to help understand the present.
The Qinshihuang Mausoleum - built for the ascending Emperor as he embarked upon his campaign of conquering neighbouring states from 246BCE - consists of a large outer wall, stone armour, a smaller inner wall and a number of offices surrounding the central tomb.
The centre of the complex was designed to mirror the urban plan of the capital, Xianyan, according to UNESCO.
It must have taken decades to construct, the level of detail showing the wealth and status of Qin Shi Huang and those buried alongside him.
Indeed, even the terracotta warriors to his east, built to protect him in the afterlife, are all different, built with painstaking care from clay and sculpted into realistic figures by hand.
Protected on all sides, the complex remained hidden until 1974.
The primary concern since has been damaging the structure - though as late as last year fears remained about the possibility of lethal boobytraps.
Testing of the soil around the site has revealed mercury traces 100 times higher than normal.
And so, permission to carefully sweep away the dust and extract delicate artefacts has been given with caution.
Preliminary work has been carried out on the (possible) tomb of Prince Gao already, with items dated to the late Qin period.
It means they could have only been buried within the first three or four years of Qin's death, according to The Times.
A skull found in the tomb was revealed to belong to a male. And a premolar found in it was in good condition, with implications the owner was between 18 and 22-years-of-age, and well-nourished.
Experts say this is consistent with it belonging to Prince Gao - but more evidence will be needed to be conclusive.
Some experts are skeptical. Jiang Wenxiao suggested that the tomb could 'belong to a high-ranking nobleman or army chief', as reported by The Times.
Relics found in and around the tomb so far give some indication of status in life. The coffin, badly-decayed, was found surrounded by weapons, armour and various household items intended for use in the afterlife.
Some 6,000 bronze coins were also found alongside the casket, as well as jade treasures and gold and silver camels. Until now, they had only been associated with later periods in Chinese history.
Hard identifying evidence might look like a personal seal belonging to Prince Gao, or some other record that matches with Sima Qian's history.
The tomb was one of nine discovered in 2011. Half the world away, archaeologists continue to uncover secrets of the ancient world, constantly updating the historical record.
Whether or not the tomb belongs to Prince Gao, or to a nobleman, is to be seen.
But the truths they uncover will help us better understand where we came from - and in turn, ourselves.
True or not, these ancient legends reveal much about how we perceive ourselves, our human fallibilities and intrigues, and the commonalities through the ages that bring us closer together.