William A. Jackson was a spy

Espionage

Espionage or spying involves an individual obtaining information that is considered secret or confidential without the permission of the holder of the information. Espionage is inherently clandestine, lest the legitimate holder of the information change plans or take other countermeasures once it...

 for the Union

Union (American Civil War)

During the American Civil War, the Union was a name used to refer to the federal government of the United States, which was supported by the twenty free states and five border slave states. It was opposed by 11 southern slave states that had declared a secession to join together to form the...

 forces during the American Civil War

American Civil War

The American Civil War was a civil war fought in the United States of America. In response to the election of Abraham Lincoln as President of the United States, 11 southern slave states declared their secession from the United States and formed the Confederate States of America ; the other 25...

. A household slave

Slavery

Slavery is a system under which people are treated as property to be bought and sold, and are forced to work. Slaves can be held against their will from the time of their capture, purchase or birth, and deprived of the right to leave, to refuse to work, or to demand compensation...

 and coachman

Coachman

A coachman is a man whose business it is to drive a coach, a horse-drawn vehicle designed for the conveyance of more than one passenger — and of mail — and covered for protection from the elements...

 of Jefferson Davis

Jefferson Davis

Jefferson Finis Davis , also known as Jeff Davis, was an American statesman and leader of the Confederacy during the American Civil War, serving as President for its entire history. He was born in Kentucky to Samuel and Jane Davis...

, President of the Confederate States of America

President of the Confederate States of America

The President of the Confederate States of America was the Head of State and Head of Government of the Confederate States of America, which was formed from the states which declared their secession from the United States, thus precipitating the American Civil War. The only person to hold the...

, he observed communications between Davis and other Confederate

Confederate States of America

The Confederate States of America was a government set up from 1861 to 1865 by 11 Southern slave states of the United States of America that had declared their secession from the U.S...

 officials. When he escaped and fled to the north in 1861, he gave the Union detailed information about Confederate military deployments, supply problems, and planning. The information was recognized at the time as valuable to the Union war efforts. Little known for many years, Jackson's life was recognized more recently as part of the larger issue of Black Dispatches

Black Dispatches

Black Dispatches was a common term used among Union military men in the American Civil War for intelligence on Confederate forces provided by Negroes...

, studied among others by the United States Central Intelligence Agency

Central Intelligence Agency

The Central Intelligence Agency is a civilian intelligence agency of the United States government. It is an executive agency and reports directly to the Director of National Intelligence, responsible for providing national security intelligence assessment to senior United States policymakers...

's Center for the Study of Intelligence.