While Britain had ended its involvement in the Atlantic Slave Trade in 1807 and enslavement had been abolished in the British Empire in 1833, several other nations continued the policy. Most prominent of these were the United States of America, Spain and Portugal. As Portuguese traders began to send larger numbers of enslaved Africans to the former colony of Brazil, Britain increasingly sought to end enslavement in Africa through negotiation with West African kingdoms and raids on foreign ships. In the late 1840s, the naval officer Frederick E. Forbes served in West Africa with the frigate HMS Penelope on such a mission. In 1849-50, he was sent on the kingdom of Dahomey (now Benin) in an unsuccessful attempt to persuade its ruler, King Ghezo (r. 1818–59) to abolish enslavement.
Throughout his reign, Ghezo, who had taken the throne following a coup, was faced with domestic dissent. By the 1840s, this had developed into two factions with enslavement as a major issue: the ‘Elephant’ with Ghezo at its head supported the continuation of enslavement, and the ‘Fly’, which favoured abolition. When Forbes arrived in Dahomey, his requests for abolition were rejected by Ghezo who argued that its continuation was integral to the survival of the state, which had become reliant on the profits received by trading with Europeans. Ghezo instead suggested that enslavement could be gradually ended if Britain encouraged the expansion of trade in Dahomey palm oil to the detriment of the neighbouring Egba state of Abeokuta with whom Dahomey was at war.

These offers were refused and in March 1851, the Royal Navy started a blockade of Dahomey ports. Ghezo then offered to end enslavement if he was paid reparations for the loss of income, but Britain again rejected the proposal. In January 1852, Ghezo agreed to end the transport of enslaved people from Dahomey ports but continued to transport people to neighbouring states from which they were then sent to the Americas. For several years in the 1850s, Ghezo gradually lowered the numbers of people Dahomey enslaved and reduced the practice of human sacrifice, a custom earlier British missions to the country reported as barbaric. In 1858-9, he became increasingly antagonistic to Britain and resumed many of the enslavement policies he followed earlier in his reign.

This two-volume account of the 1849-50 mission was published by Forbes in 1851.