Negotiations with the French government produced a conditional agreement to provide four modern wood and iron composite steam clipper corvettes for long-distance cruising. These screw corvettes would have been the equal of any U.S. Navy cruisers.
In June 1863 John Slidell, the Confederate commissioner to France, asked Emperor Napoleon III in a private audience if it would be possible for the Confederate government to build ironclad warships in France. Arming ships of war for a recognized belligerent like the Confederate States would have been illegal under French law, but Slidell and Confederate agent James D. Bulloch were confident that the French emperor would be able to circumvent his own laws more easily than could the British government. Napoleon III agreed to the building of ironclads in France on the condition that their destination remain a secret. The following month Bulloch entered a contract with Lucien Arman, an important French shipbuilder and a personal confidant of Napoleon III, to build a pair of ironclad rams capable of breaking the Union blockade. To avoid suspicion, the ships' guns were manufactured separately in England and they were named Cheops and Sphynx to encourage rumors that they were intended for the Egyptian navy. Maury specified that the ship was to have sufficient seaworthiness to cross the Atlantic, a high spread of canvas, less than fifteen feet draft, and a speed of fifteen or sixteen knots. These shallow-draft ironclad wooden ships were designed with a brig sailing rig and twin-screw steam auxiliary propulsion. With the screw corvettes they could present a dangerous challenge to the Union navy on the high seas, potentially capable of overwhelming smaller squadrons on individual blockading stations.