Walls of Benin: The Great Earthworks of the Benin Kingdom

The Walls of Benin are a vast system of earthworks, made of deep ditches and earth banks, built around Benin City and across the surrounding region in what is now southern Nigeria. Known in the Edo language as iya, they were dug over several centuries, possibly from around 800, with the main city walls completed by the 15th century. Their total length has been estimated at many thousands of kilometres, making them one of the largest earthwork systems built by hand anywhere in the world.

The Benin Kingdom

The Benin Kingdom was founded by the Edo people in the forest region west of the Niger River. Its rulers, called obas, built a powerful state centred on Benin City, which became famous for its royal palace, its guilds of craftsmen and its brass and bronze sculpture. The kingdom reached its height between the 15th and 17th centuries.

According to Edo tradition, an earlier line of rulers, the Ogiso, was followed around the 12th or 13th century by the present dynasty of obas. The earthworks are older than many of these events, and their story is closely tied to the long growth of settlement in the region.

What the walls are

Each iya consists of a ditch dug into the ground with the excavated earth piled up beside it to form a bank. The soil of the region is a deep, red, clay-rich earth that holds its shape well, which allowed steep sides. Unlike the stone walls of European or Asian cities, the Benin walls were not built up from bricks but carved out of the land.

There are two broad groups. The first is the system of walls around Benin City itself, including the great inner city wall. The second, far larger in total, is a network of rural earthworks spread over an area of thousands of square kilometres, enclosing villages and their farmland.

The city walls

The British archaeologist Graham Connah surveyed and excavated the city earthworks in the 1960s. He found that the innermost wall around the old city formed a circuit of about 11.6 kilometres. From the bottom of the ditch to the top of the bank, it measured up to about 17 metres in height in places.

Connah calculated that digging the inner city wall involved moving a huge volume of earth. By his estimate, about 5,000 labourers would have needed some three months of dry-season work to dig it, or a smaller force of around a thousand men several dry seasons. Radiocarbon and other evidence led him to suggest that the inner wall was built by the mid-15th century.

Benin oral tradition links the walls to particular obas. Oba Oguola, often dated to the late 13th or 14th century, is credited with ordering the first moats around the city. Oba Ewuare, who reigned in the mid-15th century, is remembered for rebuilding Benin City, dividing it into quarters and digging or deepening the great inner moat. Connah’s dating fits well with the tradition about Ewuare.

The rural earthworks

The British archaeologist Patrick Darling studied the rural earthworks from the late 1960s onwards. He found that the countryside around Benin City and the neighbouring Esan (Ishan) region was criss-crossed by banks and ditches, forming irregular enclosures that fitted against one another like cells in a honeycomb.

Darling interpreted these as the boundaries of individual communities. Each village dug an earthwork around its land, and as new settlements split off and cleared new forest, they dug their own. Over centuries, this produced a dense, interlocking pattern.

In the 1990s Darling estimated that the earthworks totalled about 16,000 kilometres in length, enclosing some 6,500 square kilometres and around 500 communities. He suggested the earliest may date from around 800 and that building continued until the 15th century or later. These figures are estimates based on partial surveys and limited dating, and later researchers have treated them with caution.

How they were built

The earthworks were dug with simple tools, such as iron hoes and digging sticks, and the earth was carried in baskets. No wheeled vehicles or draught animals were used. Work was probably done in the dry season, between the annual rains, when farming demanded less labour and the soil was firmer.

Darling estimated that the whole network might represent some 150 million hours of digging, spread over many generations. For the city walls, the oba could call on labour from the population as a form of service owed to the king. For the rural earthworks, the work was probably organised by village heads and family groups, each responsible for a section.

Purpose

The earthworks probably served several purposes at once. They marked boundaries between communities and their land, and they slowed down attackers, wild animals and raiders. In the city, the great walls also had a symbolic and political role, separating the royal capital from the countryside and displaying the power of the oba, who could command labour on a vast scale.

Entry to the city was through gates, which could be closed and guarded. European visitors from the 16th century onwards described Benin City as a large, well-ordered city with broad streets, protected by walls and ditches.

The end of the walls

In February 1897 a British force of around 1,200 men attacked Benin City in the Benin Expedition of 1897, launched in retaliation for the killing of members of a British party in January. The city was captured on 18 February, its palace burned and thousands of works of art, including the famous Benin bronze plaques, were taken to Britain.

The walls offered little protection against modern weapons. Under colonial rule they were neglected, and in the 20th century the growth of Benin City led to roads being cut through them and houses built on and around them. Today many sections are filled with refuse or eroded, although others survive. Recent surveys using satellite imagery and fieldwork have mapped what remains.

Myths and facts

• Myth: the Walls of Benin are four times longer than the Great Wall of China. Fact: this comparison, popularised in the late 1990s, sets the estimated total of thousands of small rural earthworks against a single frontier system. The structures are not comparable, and the Benin total is itself an estimate.
• Myth: the walls can be seen from space. Fact: like the Great Wall, they are too narrow to be seen with the naked eye from orbit, though they can be traced in satellite images.
• Myth: the walls were built all at once by one king. Fact: they were dug over many centuries by many communities, with the city walls credited to several obas.

Timeline

• c. 800 (estimated): Possible beginnings of rural earthwork building, according to Patrick Darling.
• c. 12th–13th century: The present dynasty of obas emerges, according to Edo tradition.
• Late 13th–14th century: Oba Oguola is credited with the first moats around Benin City.
• Mid-15th century: Oba Ewuare rebuilds Benin City; the great inner wall is completed.
• 1960s: Graham Connah surveys and excavates the city walls.
• 1897, February: British forces capture and burn Benin City.
• 1990s: Darling estimates the rural earthworks at about 16,000 kilometres.

Why it matters

The Walls of Benin are one of the great engineering achievements of pre-industrial Africa, built entirely by human labour with simple tools. They show the long history of settlement, organisation and political power in the Benin region, centuries before European contact. Their destruction and neglect since 1897 also make them a pressing case for heritage protection in Nigeria.