40, Department of the Gulf, was issued by Major General Nathaniel P. Banks and stated the intent of forming a corps-sized unit composed of colored soldiers: The major-general commanding the department proposes the organization of a corps d'armee of colored troops, to be designated as the Corps d'Afrique.

[1] The Corps d'Afrique was formed from the four infantry regiments of the Louisiana Native Guard raised by Major General Benjamin F. Butler (before Banks replaced him as commander of the Department of the Gulf) and the five colored infantry regiments raised by Brigadier General Daniel Ullman.

Though the Louisiana Native Guard regiments had black officers, including Andre Cailloux and P. B. S. Pinchback, eventually Banks would purge the black officers of the Louisiana Native Guard[3] and replace them with white soldiers from other units, primarily from the North.

[2] First Lieutenant Charles Sauvinet would be the only black officer from the Louisiana Native Guard to retain his commission until the end of the war.

Utilizing both voluntarily enlistment and conscription of freedmen and escaped slaves, the corps eventually grew to over twenty regiments[2] before being absorbed into the Bureau of Colored Troops in April 1864.