Neptune was an ironclad barbette ship of the French Navy built in the 1880s and early 1890s. She was the second member of the , which included two other vessels. The Marceau class was based on the earlier of barbette ships, but with smaller guns: four weapons compared to the three guns of the earlier vessels. They introduced the lozenge arrangement for their main battery that became common for many French capital ships built in the 1890s. Neptune and her sister ships suffered from a number of problems, including poor stability, insufficient armor protection, and excessive displacement. Neptune, completed in 1892, had a relatively short and uneventful career, which she spent in the Mediterranean Squadron conducting training exercises. New pre-dreadnought battleships began to enter service in the mid-1890s, which displaced the Marceaus to the Reserve Division, where they were used as training ships. Neptune and her sisters were scheduled to be modernized with new water-tube boilers in the early 1900s, but by the time the new boilers were delivered, ironclads like the Marceaus were obsolete, and so no work was carried out. She saw no further active service, was struck from the naval register in 1908, and she was used as a target ship from then until 1912. Sunk in weapons tests in 1912, she was raised in 1913 and sold to ship breakers and dismantled. Design The Marceau class of ironclad barbette ships was initially intended to be similar to the , but by the time work on the design was being completed in 1880, the very large guns used in the earlier vessels had fallen out of favor in the French Navy. Lighter guns allowed a fourth weapon to be added to the main battery, which were rearranged into a lozenge layout that would be used in most French capital ships built over the following ten years. The class was to have comprised four vessels, but the first unit, had to be redesigned with a reduced armament after construction began when it became apparent that the initial design was not feasible on the specified dimensions. Work on the remaining three vessels had not yet begun, so their design could be enlarged to accommodate the intended armament. The design of the Marceau-class ships was revised repeatedly during construction, and by the time they were completed, they were seriously overweight, which submerged much of their belt armor and degraded their