In 1821 the British Company of Merchants at Cape Coast handed its forts on the Gold Coast (Cape Coast, Anomabu, Accra, Beyin, Dixcove, Kommenda, Winneba, Sekondi, Prampram and Tantamkweri), like those in the Gambia, to the British Crown as represented by the Governor of Sierra Leone. The Governor there at this time was Sir Charles MacCarthy, who sailed to Cape Coast at once to survey his new responsibilities. MacCarthy's mandate was to impose peace and to end the slave trade. He concluded that British interests in the Gold Coast required the crushing of the powerful Ashanti (Asante) Empire.
In 1824, after the Ashanti executed a Fante serving in a British garrison for insulting the asantehene(king of the Ashanti), the British responded with a military expedition into the Ashanti Empire. A 10,000 man Ashanti force massed near Bonsaso to face the British expeditionary force. At the battle of Nsamankow (January 22, 1824) the Ashanti not only outnumbered the British but also used superior tactics. MacCarthy was killed, and most of his force was wiped out.
By a strange chance, that same day (January 21, 1824) the asantehene, Osei Bonsu, died in Kumasi, and was succeeded by Osei Yaw Akoto. The new king maintained Ashanti resistance to the British by demanding that the latter give up Kwadwo Otibu of Denkyera, their ally and an enemy of the Ashanti. At another battle at Efutu a joint Denkyera and British force was defeated. But the Ashanti had now reached the highest point of their success. When they tried to storm the strongly fortified British headquarters at Cape Coast, they failed.
Whilst the Ashanti recovered their strength back in Ashanti during the next two years (1824-6), the British were building up a powerful alliance with the Fante, Ga, Akim and Denkyera people, all of whom were now thoroughly afraid of the Ashanti. In 1826 a reorganized and re-equipped Ashanti force invaded the coastal regions in an attempt to bring the region under Ashanti control. The Anglo-African alliance defeated the Ashanti at the battle of Dodowa [also known as Katamanso or Akantamasu] on August 7, 1826. During the fighting on the Accra Plains the British used Congreve rockets, which frightened the Ashanti warriors, who fled back to Kumasi. The new governor, Sir Neil Campbell, however, found the Ashanti still strong enough to refuse to sign any treaties.
In 1828, the British government reasoned that if it withdrew from the scene a reconciliation between the merchants and peoples on the coast and the asantehene might prove easier to make. It therefore gave instructions to the Governor of Sierra Leone, Sir Neil Campbell, that he should not make alliances with African peoples who would expect Britain to protect them, and gave orders that British officials and garrisons should be withdrawn from the Gold Coast forts. The forts, however, were to remain British territory, and the British Government paid the London Committee of Merchants 4,000 pounds a year to maintain them. The settlements were to be governed by a Governor and an elected Council which was to have jurisdiction only over British forts and harbors and the people residing therein.
In 1830 the London Committee sent out as President of the Council (or Governor) Captain George Maclean who, in 1831, came to terms with the Ashanti. He achieved this in spite of the fact that he had not any real power and little backing from the British government. Furthermore attempts of the British government to come to terms with the Ashanti after Dodowa had been opposed by the coastal peoples, who feared that the Ashanti would again assert their claim to suzerainty over them. Even among the merchants there were some who thought Maclean should confine his activities and authority to those actually living within the British forts. By the terms of the treaty signed in 1831 by the Governor (Maclean), two Ashanti delegates, six Fante chiefs, representatives of Assin, Tufel and Denkyera and other African chiefs, the asantehene paid the British 600 ounces of gold, gave two hostages from the royal family and recognized the independence of Denkyera and Assin. The gold and the hostages were later returned to Kumasi. One estimate of casualties suggests the warfare resulted in 3000 Ashanti deaths and 100 British deaths.