Spiro Mounds: Mississippian Treasure and Its 1930s Looting

The Spiro Mounds are a group of earthen mounds on the Arkansas River in eastern Oklahoma, built between about 900 and 1450 by Caddoan-speaking peoples of the Mississippian world. At its height Spiro was one of the most important ceremonial centres in North America, and its great burial mound held a treasury of shell, copper, stone and textile art. Much of that treasure was dug out and sold by commercial looters in the 1930s, in one of the worst acts of archaeological destruction in the United States.

Background: the Mississippian world

Between about 800 and 1600 many farming societies across the river valleys of the American Midwest and Southeast shared what archaeologists call the Mississippian culture. They grew maize, lived in chiefdoms ruled by hereditary elites, and built large flat-topped earthen mounds for temples and leaders’ houses. The largest Mississippian centre was Cahokia near modern St Louis; others included Moundville in Alabama and Etowah in Georgia.

Spiro lay at the western edge of this world, where the eastern woodlands meet the southern Plains. Its builders were Caddoan speakers, ancestors of the Caddo and Wichita peoples. Their location along the Arkansas River placed them on routes connecting the Mississippi Valley, the Plains, the Gulf Coast and the Southwest.

The site and its mounds

The Spiro site contains about a dozen mounds spread over both a lower terrace by the river and higher ground nearby. Some were platform mounds that supported buildings; others covered the remains of earlier structures. The most important is the Craig Mound, a long ridge-shaped mound with four connected lobes, which was the main burial mound of the community’s elite.

Occupation at Spiro began before 900, and the site grew into a ceremonial centre in the following centuries. Archaeologists think that relatively few people lived at the mound centre itself; most of the population lived in farmsteads and villages along the river valley. Spiro’s leaders and priests used the centre for burials, ceremonies and gatherings.

Around 1400 a hollow chamber within the Craig Mound, often called the Great Mortuary, was filled with burials and objects. It was formed by a framework of cedar poles covered with earth, and its dry, sealed conditions preserved perishable materials such as textiles, wood, feathers and basketry that rarely survive in eastern North America.

Treasures of the Craig Mound

The objects found in the Craig Mound are among the finest works of Native American art from before European contact. They include cups and gorgets (pendants worn at the throat) made from large marine whelk shells, engraved with warriors, birds of prey, serpents, spiders and dancing figures. The shells came from the Gulf of Mexico or the Atlantic coast, hundreds of kilometres away.

Other finds include embossed copper plates showing winged human figures, ceremonial maces and axes of polished stone, and carved stone pipes in human and animal form, among them the famous “Big Boy” effigy pipe. There were also thousands of shell and pearl beads, woven fabrics, cloaks and conch shell trumpets. Some materials came from great distances, including copper from the Great Lakes region and obsidian from Mexico and the Rocky Mountains.

These images belong to a shared religious art across the Mississippian world, known as the Southeastern Ceremonial Complex or Mississippian Ideological Interaction Sphere. Its themes, such as the falcon-dancer and the cosmic serpent, reflect beliefs about the upper and lower worlds, warfare, fertility and the ancestors.

Decline

Spiro declined after about 1400, and by around 1450 the mound centre was no longer used for major ceremonies. Possible reasons include drought, conflict and changes in long-distance trade and political networks, which affected many Mississippian centres at this time. The people of the region did not disappear; they continued to live in the wider Arkansas and Red River valleys and became the Caddoan peoples encountered by later European explorers.

The looting of 1933–1935

In 1933, during the Great Depression, a group of six local men formed the Pocola Mining Company and leased the right to dig in the Craig Mound from the landowners. They dug tunnels into the mound and broke into the Great Mortuary, removing thousands of objects and selling them to dealers and collectors. Many fragile items crumbled in the process, and the cedar framework and burials were destroyed.

The finds caused a sensation, and newspapers compared Spiro to the tomb of Tutankhamun, discovered in Egypt only a decade earlier. Archaeologists and others protested, and in 1935 Oklahoma passed a law requiring a licence to excavate antiquities. The miners’ lease ran out the same year, leaving the mound riddled with tunnels and partly collapsed.

From 1936 to 1941 the University of Oklahoma, working with the federal Works Progress Administration under Forrest E. Clements, carried out scientific excavations of what remained. Their work recovered important information, but the heart of the Great Mortuary had already been destroyed. Spiro objects are now scattered among museums and private collections across North America and Europe.

Myths and facts

In the nineteenth century many Americans believed that the great earthworks of the Mississippi Valley had been built by a vanished “Mound Builder” race unrelated to Native Americans. This myth was used to belittle Indigenous peoples and justify their removal. Archaeology has long since shown that mounds such as Spiro’s were built by the ancestors of modern Native American nations, in Spiro’s case Caddoan speakers.

The newspaper label “King Tut of America” also gives a misleading picture. Spiro was not the tomb of a single king surrounded by gold. The Great Mortuary held the remains and possessions of many people, possibly gathered from earlier burials and reburied together, and its value lay in shell, copper, stone and fibre objects rather than precious metals. Historians also stress that the looters were mostly poor local men during the Depression, while dealers and collectors elsewhere made the largest profits.

Timeline

• c. 800–900: Earliest occupation of the Spiro site.
• c. 900–1250: Spiro develops as a Caddoan Mississippian ceremonial centre.
• c. 1400: The Great Mortuary in the Craig Mound is filled with burials and offerings.
• c. 1450: Major ceremonial use of the site ends.
• 1933: The Pocola Mining Company begins digging in the Craig Mound.
• 1935: Oklahoma passes an antiquities law; the commercial digging ends.
• 1936–1941: University of Oklahoma and WPA excavations.
• 1978: The Spiro Mounds Archaeological Center opens to the public.

Legacy

Spiro was listed on the National Register of Historic Places in 1969, and the Spiro Mounds Archaeological Center opened in 1978. In recent decades researchers have worked to trace and catalogue scattered Spiro objects, and the Caddo Nation and Wichita and Affiliated Tribes have taken a growing role in how their ancestors’ site is presented.

The looting of Spiro became a turning point in American attitudes to archaeological heritage. It helped push states and the federal government towards stronger protection of sites and, decades later, towards laws such as the Native American Graves Protection and Repatriation Act of 1990.

Why it matters

Spiro reveals the artistic richness and wide connections of the Mississippian world at its western edge. It also stands as a warning: the destruction of the Craig Mound in the 1930s erased knowledge that can never be recovered, and shaped how North America protects its ancient sites today.