By the mid-nineteenth century, the British had assumed a protectorate over the non-Ashante peoples of the coast. Continued Ashante attacks on British and non-Ashante settlements resulted in a successful punitive expedition by the British and their African allies against the Ashante capital at Kumasi in 1874. Thereafter, the Gold Coast was formally declared a British colony. Still, it took another quarter of a century to fully defeat the Ashante and establish British administration over the whole territory of what is now Ghana. From the 1920s, the British began to develop an export economy, based on cocoa, timber, and manganese. By bringing together large numbers of persons from different ethnic groups in these industries, the British incidentally established the beginnings of a Ghanaian nationalism.