I have posted the parole letters and conversations taken from the Official Records of the War of the Rebellion regarding Captain Alfred Gibbs. These correspondences outline the period from when Gibbs was surrendered by Issac Lynde and sent to Detroit to await his parol.
The exchange of prisoners of war between the Union and the Confederacy used the system where captured soldiers were released from detention on the condition that they pledged not to fight again. These prisoners could not be on the battlefield until exchanged for an equal number of soldiers from the other side and of equal rank was formally approved by both sides.
The parole system was used throughout the Civil War to reduce the number of prisoners held by both sides and alleviate the overcrowding and harsh conditions in many military prison camps.
The respective armies administered the parole system, and prisoners were often held in designated parole camps until formally exchanged. The exchange process was often slow and complex, and it was common for soldiers to spend months or even years in parole camps before being officially released. The parole system was eventually replaced by more formalized methods of prisoner exchange, such as the Dix-Hill Cartel, which was established in 1862.