The construction of the tomb was described by historian Sima Qian (145–90 BCE) in his most noted work Shiji, written a century after the mausoleum's completion. Work on the mausoleum began in 246 BCE soon after Emperor Qin (then aged 13) ascended the throne, and the project eventually involved 700,000 workers. Geographer Li Daoyuan, writing six centuries after the First Emperor's death, recorded in Shui Jing Zhu that Mount Li was a favoured location due to its auspicious geology, "famed for its jade mines, its northern side was rich in gold, and its southern side rich in beautiful jade; the First Emperor, covetous of its fine reputation, therefore chose to be buried there". Sima Qian wrote that the First Emperor was buried with palaces, towers, officials, valuable artifacts and wondrous objects. According to this account, 100 flowing rivers were simulated using mercury, and above them the ceiling was decorated with heavenly bodies below which were the features of the land. Some translations of this passage refer to "models" or "imitations;" however, those words were not used in the original text, which makes no mention of the terracotta army.
High levels of mercury were found in the soil of the tomb mound, giving credence to Sima Qian's account.
Later historical accounts suggested that the tomb had been looted by Xiang Yu, a contender for the throne after the death of the first emperor. However, there are indications that the tomb may not have been plundered.
The Terracotta Army was discovered on 29 March 1974 to the east of Xi'an in Shaanxi province by farmers digging a water well approximately 1.6 kilometres (0.99 mi) east of the Qin Emperor's tomb mound at Mount Li (Lishan), a region riddled with underground springs and watercourses. For centuries, occasional reports mentioned pieces of terracotta figures and fragments of the Qin necropolis – roofing tiles, bricks and chunks of masonry. This discovery prompted Chinese archaeologists to investigate, revealing the largest pottery figurine group ever found in China.
A museum complex has since been constructed over the area, with the largest pit enclosed within with a large structure.
The Terracotta Army is part of a much larger necropolis. Ground-penetrating radar and core sampling have measured the area to be approximately 38 square miles (98 square kilometers).
The necropolis was constructed as a microcosm of the emperor's imperial palace or compound, and covers a large area around the tomb mound of the first emperor. The earthen tomb mound is located at the foot of Mount Li and built in a pyramidal shape, and is surrounded by two solidly built rammed earth walls with gateway entrances. The necropolis consists of several offices, halls, stables, other structures as well as an imperial park placed around the tomb mound.
The warriors stand guard to the east of the tomb. Up to 5 metres (16 ft) of reddish, sandy soil had accumulated over the site in the two millennia following its construction, but archaeologists found evidence of earlier disturbances at the site. During the excavations near the Mount Li burial mound, archaeologists found several graves dating from the eighteenth and nineteenth centuries, where diggers had apparently struck terracotta fragments. These were discarded as worthless and used along with soil to back fill the excavations.
The tomb appears to be a hermetically-sealed space the size of a football pitch. The tomb remains unopened, possibly due to concerns over preservation of its artifacts. For example, after the excavation of the Terracotta Army, the painted surface present on some terracotta figures began to flake and fade. The lacquer covering the paint can curl in fifteen seconds once exposed to Xi'an's dry air and can flake off in just four minutes.
Four main pits approximately 7 metres (23 ft) deep have been excavated. These are located approximately 1.5 kilometres (0.93 mi) east of the burial mound. The soldiers within were laid out as if to protect the tomb from the east, where all the Qin Emperor's conquered states lay.
Pit one, which is 230 metres (750 ft) long and 62 metres (203 ft) wide, contains the main army of more than 6,000 figures. Pit one has 11 corridors, most of which are more than 3 metres (9.8 ft) wide and paved with small bricks with a wooden ceiling supported by large beams and posts. This design was also used for the tombs of nobles and would have resembled palace hallways when built. The wooden ceilings were covered with reed mats and layers of clay for waterproofing, and then mounded with more soil raising them about 2 to 3 metres (6 ft 7 in to 9 ft 10 in) above the surrounding ground level when completed.
Pit two has cavalry and infantry units as well as war chariots and is thought to represent a military guard. Pit three is the command post, with high-ranking officers and a war chariot. Pit four is empty, perhaps left unfinished by its builders.
Some of the figures in pit one and two show fire damage, while remains of burnt ceiling rafters have also been found. These, together with the missing weapons, have been taken as evidence of the reported looting by Xiang Yu and the subsequent burning of the site, which is thought to have caused the roof to collapse and crush the army figures below. The terracotta figures currently on display have been restored from the fragments.
Other pits that formed the necropolis also have been excavated. These pits lie within and outside the walls surrounding the tomb mound. They variously contain bronze carriages, terracotta figures of entertainers such as acrobats and strongmen, officials, stone armour suits, burials sites of horses, rare animals and labourers, as well as bronze cranes and ducks set in an underground park.
The terracotta figures are life-sized. They vary in height, uniform, and hairstyle in accordance with rank. The faces appear different for each individual figure, scholars however have identified 10 basic face shapes. The figures are of these general types: armored warriors; unarmored infantrymen; cavalrymen who wear a pillbox hat; helmeted driver of chariots with more armor protection; spear-carrying charioteers; kneeling archers who are armored; standing archers who are not; as well as generals and other lower-ranking officers. There are however many variations in the uniforms within the ranks, for example, some may wear shin pads while others not; they may wear either long or short trousers, some of which may be padded; and their body armors vary depending on rank, function, and position in formation. There are also terracotta horses placed among the warrior figures.
Originally, the figures were painted with bright pigments, variously coloured pink, red, green, blue, black, brown, white and lilac. The coloured lacquer finish and individual facial features would have given the figures a realistic feel. However, much of the colour coating had flaked off or become greatly faded.
Some scholars have speculated a possible Hellenistic link to these sculptures, due to the lack of life-sized and realistic sculptures prior to the Qin dynasty. They argued that potential Greek influence is particularly evident in some terracotta figures such as those of acrobats, as well as the technique used for casting bronze sculptures.
The terracotta army figures were manufactured in workshops by government laborers and local craftsmen using local materials. Heads, arms, legs, and torsos were created separately and then assembled by luting the pieces together. When completed, the terracotta figures were placed in the pits in precise military formation according to rank and duty.
The faces were created using molds, and at least ten face molds may have been used. Clay was then added after assembly to provide individual facial features to make each figure appear different. It is believed that the warriors' legs were made in much the same way that terracotta drainage pipes were manufactured at the time. This would classify the process as assembly line production, with specific parts manufactured and assembled after being fired, as opposed to crafting one solid piece and subsequently firing it. In those times of tight imperial control, each workshop was required to inscribe its name on items produced to ensure quality control. This has aided modern historians in verifying which workshops were commandeered to make tiles and other mundane items for the terracotta army.
Most of the figures originally held real weapons such as spears, swords, or crossbows, and the use of actual weapons would have increased the figures' realism. Most of the original weapons, however, were looted shortly after the creation of the army, or have rotted away. Nevertheless, many weapons such as swords, spears, lances, battle-axes, scimitars, shields, crossbows, and arrowheads have been found in the pits. Over 40,000 bronze items of weaponry have been recovered from the pits, with most of these arrowheads which are usually found in bundles of 100 units. Studies of these arrowheads suggests that they were produced in small units of self-sufficient, autonomous workshops that produced finished items in a production process referred to as cellular production or Toyotism. There are also hundreds of crossbow triggers, and smaller number of other weapons such as bronze swords, and daggers.
Some of these weapons, such as the swords are sharp and were coated with a 10–15 micrometre layer of chromium dioxide that kept the swords rust-free for 2,000 years. The swords contain an alloy of copper, tin, and other elements including nickel, magnesium, and cobalt. Some carry inscriptions that date their manufacture to between 245 and 228 BCE, indicating that they were used as weapons before their burials.
An important element of the army is the chariot, of which four types were found. In battle the fighting chariots formed pairs at the head of a unit of infantry. The principal weapon of the charioteers was the ge or dagger-axe, an L-shaped bronze blade mounted on a long shaft used for sweeping and hooking at the enemy. Infantrymen also carried ge on shorter shafts, ji or halberds and spears and lances. For close fighting and defence, both charioteers and infantrymen carried double-edged straight swords. The archers carried crossbows, with sophisticated trigger mechanisms, capable of shooting arrows farther than 800 metres (2,600 ft).
A collection of 120 objects from the mausoleum and 12 terracotta warriors were displayed at the British Museum in London as its special exhibition "The First Emperor: China's Terracotta Army" from 13 September 2007 to April 2008. This exhibition made 2008 the British Museum's most successful year and made the British Museum the United Kingdom's top cultural attraction between 2007 and 2008. The exhibition brought the most visitors to the museum since the King Tutankhamun exhibition in 1972. It was reported that the 400,000 advance tickets sold out so fast that the museum extended its opening hours until midnight. According to The Times, many people had to be turned away, despite the extended hours. During the day of events to mark the Chinese New Year, the crush was so intense that the gates to the museum had to be shut. The Terracotta Army has been described as the only other set of historic artifacts (along with the remnants of wreck of the RMS Titanic) that can draw a crowd by the name alone.
Warriors and other artifacts were exhibited to the public at the Forum de Barcelona in Barcelona between 9 May and 26 September 2004. It was their most successful exhibition ever. The same exhibition was presented at the Fundación Canal de Isabel II in Madrid between October 2004 and January 2005, their most successful ever. From December 2009 to May 2010 the exhibition was shown in the Centro Cultural La Moneda in Santiago de Chile.
The exhibition traveled to North America and visited museums such as the Asian Art Museum of San Francisco, Bowers Museum in Santa Ana, California, Houston Museum of Natural Science, High Museum of Art in Atlanta, National Geographic Society Museum in Washington, D.C. and the Royal Ontario Museum in Toronto. Subsequently, the exhibition traveled to Sweden and was hosted in the Museum of Far Eastern Antiquities between 28 August 2010 and 20 January 2011. An exhibition entitled 'The First Emperor – China's Entombed Warriors', presenting 120 artifacts was hosted at the Art Gallery of New South Wales, between 2 December 2010 and 13 March 2011. An exhibition entitled "L'Empereur guerrier de Chine et son armée de terre cuite" ("The Warrior-Emperor of China and his terracotta army"), featuring artifacts including statues from the mausoleum, was hosted by the Montreal Museum of Fine Arts from 11 February 2011 to 26 June 2011. In Italy, from July 2008 to November 16, 2008, five of the warriors of the terracotta army were exposed in Turin at the Museum of Antiquities, and from 16 April 2010 to 5 September 2010 were exposed nine warriors in Milan, at the Royal Palace, at the exhibition entitled "The Two Empires". The group consisted of a horse, a counselor, an archer and 6 Lancers. The "Treasures of Ancient China" exhibition, showcasing two terracotta soldiers and other artifacts, including the Longmen Grottoes Buddhist statues, was held between 19 February 2011 and 7 November 2011 in four locations in India: National Museum of New Delhi, Prince of Wales Museum in Mumbai, Salar Jung Museum in Hyderabad and National Library of India in Kolkata.
Soldiers and related items were on display from March 15, 2013, to November 17, 2013, at the Historical Museum of Bern.
In 2007, scientists at Stanford University and the Advanced Light Source facility in Berkeley, California reported that powder diffraction experiments combined with energy-dispersive X-ray spectroscopy and micro-X-ray fluorescence analysis showed that the process of producing Terracotta figures colored with Chinese purple dye consisting of barium copper silicate was derived from the knowledge gained by Taoist alchemists in their attempts to synthesize jade ornaments.
Since 2006, an international team of researchers at the UCL Institute of Archaeology have been using analytical chemistry techniques to uncover more details about the production techniques employed in the creation of the Terracotta Army. Using X-ray fluorescence spectrometry of 40,000 bronze arrowheads bundled in groups of 100, the researchers reported that the arrowheads within a single bundle formed a relatively tight cluster that was different from other bundles. In addition, the presence or absence of metal impurities was consistent within bundles. Based on the arrows’ chemical compositions, the researchers concluded that a cellular manufacturing system similar to the one used in a modern Toyota factory, as opposed to a continuous assembly line in the early days of automobile industry, was employed.
Grinding and polishing marks visible under a scanning electron microscope provide evidence for the earliest industrial use of lathes for polishing.