This resulted in the rise of two formidable indigenous states, the Fantes who were along the coast and the Asantes in the adjacent forest.
As the Asante kingdom grew in wealth and influence, they sought to eliminate the middle men (the Fantes) from the supply chain.
In 1755, the Asantehene, the king of the Asantes (who was at that time Osei Bonsu) began preparing for war with the Fantes.
A major consequence was that the Asantehene ordered Asante traders not to visit the forts in Cape Coast belonging to the British, but to deal only with the Dutch and the Danes.
Macarthy inherited a strong likelihood of war with the Asantes, but mistook it to be a local quarrel which could have no effect on the British.
Asante armies moved south early in 1824 and, on 21 January, they met and defeated a small force under Sir Charles Macarthy himself at Adamanso.
After this incident, the British decided to protect their forts and traders and leave the locals to their own devices, while the Asantes continued to wage war on the Fantes.
Under Lieutenant-Colonel Purdon, the British (with the contribution of the eastern Kings) won a decisive victory against the Asante at Katamanso on August 7, 1826.
After this, the British tried to bring peace between the Asantes and Fantes, but the coalition of coastal chiefs were unwilling to negotiate.
By February 15, George Maclean assumed the duties of the president of the council of Merchants at Cape Coast.