In the 1800s, one of the main materials traded to Britain and France from the United States was cotton. This cotton would then be utilized in factories in Britain and France to produce textiles which could then be sold in their own countries, in their colonies, and elsewhere around the world. The cotton that was traded to Britain and France came from the southern United States, where it was grown and harvested using slave labor. One of the reasons cotton production was so profitable for the South was the fact that production costs were relatively low because of slavery. This would also keep prices low for the British and French who hoped to purchase cotton for production of textiles.
In the 1860s, Britain and France had already banned slavery. Morally, these countries were opposed to slavery. The South hoped, however, that the economic benefit of trading with the Confederacy would cause Britain and France to question just how valuable the morals were.