The development of "legitimate" trade was the final phase of private and official British efforts to find a positive alternative to the traffic in slaves. Earlier aspects of such constructive interest had included the founding of the colony at Sierra Leone in 1787 as a refuge for liberated slaves, the missionary movement designed to bring Christianity to the region, and programs of exploration sponsored by learned societies and scientific groups, such as the London-based African Association.

The principal commodities of legitimate trade were palm oil and palm kernels, which were used in Europe to make soap and as lubricants for machinery before petroleum products were developed for that purpose. Although this trade grew to significant proportions--palm oil exports alone were worth £1 million a year by 1840--it was concentrated near the coast, where palm trees grew in abundance. Gradually, however, the trade forced major economic and social changes in the interior, although it hardly undermined slavery and the slave trade. Quite the contrary, the incidence of slavery in local societies actually increased.

Initially most palm oil (and later kernels) came from Igboland, where palm trees formed a canopy over the densely inhabited areas of the Ngwa, Nri, Awka, and other Igbo peoples. Palm oil was used locally for cooking, the kernels were a source for food, trees were tapped for palm wine, and the fronds were used for building material. It was a relatively simple adjustment for many Igbo families to transport the oil to rivers and streams that led to the Niger Delta for sale to European merchants. The rapid expansion in exports, especially after 1830, occurred precisely at the time slave exports collapsed. Instead, slaves were redirected into the domestic economy, especially to grow the staple food crop, yams, in northern Igboland for marketing throughout the palm-tree belt. As before, Aro merchants dominated trade, including the sale of slaves within Igboland as well as palm products to the coast. They maintained their central role in the confederation that governed the region.

The Niger Delta and Calabar, which once had been known for the export of slaves, now became famous for the export of palm oil, so much so that the delta streams were given the name the "oil rivers." The basic economic units in each town were "houses," family-operated entities that were also the focus of loyalty for those employed in them. A "house" included the extended family of the trader, both his retainers and slaves. As its head, the master trader taxed other traders who were members of his "house" and was obligated to maintain a war vessel, which was a large dugout canoe that could hold several tons of cargo and dozens of crew, for the defense of the harbor. Whenever a trader could afford to keep a war canoe, he was expected to form his own "house". Economic competition among these "houses" was so fierce that trade often erupted into armed battle between the large canoes.

Because of the hazards of climate and disease for Europeans and the absence of any authority responsive to their interests on the 1000 mainland, European merchants ordinarily moored their ships outside harbors or in the delta and used the ships as trading stations and warehouses. In time, however, they built depots onshore and eventually moved up the Niger River to stations established in the interior, like that at Onitsha, where they could bargain with local suppliers and purchase products likely to turn a profit. Some European traders switched to legitimate business only when the commerce in slaves became too hazardous. Disreputable as many of the traders had been, they often suffered from the precariousness of their position and were at the mercy of what they considered to be unpredictable coastal rulers. Accordingly, as the volume of trade increased, the British government responded to repeated requests of merchants to appoint a consul to cover the region. Consequently in 1849, John Beecroft was accredited as consul for the bights of Benin and Biafra, a jurisdiction stretching from Dahomey to Cameroon. Beecroft was the British representative to Fernando Po, where the British navy's prevention squadron was stationed.

Exploration of the Niger Basin had a commercial as well as scientific motivation, but curiosity about the course and destination of the river also played a part. The delta masked the mouth of the great river, and for centuries Nigerians chose not to tell Europeans the secrets of the interior, initially probably because no one thought to ask but by the nineteenth century because of the commercial implications. In 1794 the African Association commissioned Mungo Park, an intrepid Scottish physician and naturalist, to search for the headwaters of the Niger and follow the river downstream. Park reached the upper Niger the next year by traveling inland from the Gambia River. Although he reported on the eastward flow of the Niger, he was forced to turn back when his equipment was lost to Muslim slave traders. In 1805 he set out on a second expedition, sponsored by the British government, to follow the Niger to the sea. His mission failed, but Park and his party covered more than 1,500 kilometers, passing through the western portions of the Sokoto Caliphate, before being drowned in rapids near Bussa.

On a subsequent expedition to the Sokoto Caliphate, Hugh Clapperton learned where the Niger River flowed to the sea, but Clapperton also died before he could substantiate his information. It was his servant, Richard Lander, and Lander's brother, John, who actually demonstrated that the Niger flowed into the delta. The Lander brothers were seized by slave traders in the interior and sold down the river to a waiting European ship.

Initial attempts to open trade with the interior by way of the Niger could not overcome climate and disease, which took the lives of a third of a British riverine expedition in 1842. Use of quinine to combat malaria on similar expeditions in the 1850s enabled a Liverpool merchant, Macgregor Laird, to open the river. Laird's efforts were stimulated by the detailed reports of a pioneer German explorer, Heinrich Barth, who traveled through much of Borno and the Sokoto Caliphate and recorded information about the region's geography, economy, and inhabitants.

Data as of June 1991