Daniel Harvey Hill
On July 22, 1862, Dix and Confederate Major General Daniel Harvey Hill concluded an agreement for the general exchange of prisoners between the Union and Confederate armies. This agreement became known as the Dix-Hill Cartel. It established a scale of equivalents, where an officer would be exchanged for a fixed number of enlisted men, and also allowed for the parole of prisoners, who would undertake not to serve in a military capacity until officially exchanged. (The cartel worked well for a few months, but broke down when Confederates insisted on treating black prisoners as fugitive slaves and returning them to their previous owners.)