The practice of paroling enemy troops began thousands of years ago, at least as early as the time of Carthage. Parole allowed the prisoners' captors to avoid the burdens of having to feed and care for them while still avoiding having the prisoners rejoin their old ranks once released; it could also allow the captors to recover their own men in a prisoner exchange. Hugo Grotius, an early international lawyer, favorably discussed prisoner of war parole. During the American Civil War, both the Dix–Hill Cartel and the Lieber Code set out rules regarding prisoner of war parole. Francis Lieber's thoughts on parole later reappeared in the Declaration of Brussels of 1874, the Hague Convention, and the Geneva Convention Relative to the Treatment of Prisoners of War.