In this article, I assess how a transnational campaign against the slave trade developed in the eighteenth century, focusing on the seminal role of Quakers. Building on Keck and Sikkink's study of the international campaign against slavery in America in the mid-nineteenth century, I show how one can identify transnational advocacy on this issue more than half a century earlier. I examine the features of Quakerism - specifically the close links between American and English Quakers -and the historical circumstances that gave rise to the campaign. In particular, I assess the role of transatlantic correspondence and travel among individual Quakers and the close organizational links between the society's branches on either side of the Atlantic. I analyse the development of anti-slave trade activism according to Khagram, Riker and Sikkink's model of network development and find that this model is broadly applicable. I note, however, the change within the campaign from truly transnational (transatlantic) to predominantly domestic (British) as it changed from a coalition to a broader social movement, and as the campaign began to interact with the state, thus suggesting that the development of transnational networks is neither linear nor inevitable.
