The corps was organized under authority of General Order No. 105, U.S. War Department, dated April 28, 1863. A similar corps had existed in Revolutionary times. The Invalid Corps of the Civil War period was created to make suitable use in a military or semi-military capacity of soldiers who had been rendered unfit for active field service on account of wounds or disease contracted in line of duty, but who were still fit for garrison or other light duty, and were, in the opinion of their commanding officers, meritorious and deserving.