During the Revolution a decree (May, 1791) prohibited acquisition of all vessels of foreign build. In 1793 (Sept.) it was ordained that no foreign commodities, productions, or merchandise should be imported into France, or into any of her colonies or possessions, except directly in French ships, or in ships belonging to the inhabitants of the countries in which the articles imported were produced, or from the ordinary ports of sale or exportation. All officers and three-fourths of the crew were required to be natives of the country of which the foreign vessel bore the flag, under penalty of confiscation of vessel and cargo, and a fine enforcible under pain of imprisonment. A tonnage tax was levied on foreign ships alone. Despite this elaborate code designed for its benefit the domestic mercantile marine almost entirely disappeared during the wars of the Republic and the Empire; and after the Restoration its revival was so slow that for some time foreign ships were absolutely necessary for the supply of the French market.[BH] Still the underlying principles of the code were retained by the Restoration Government, modified in a few particulars. The modifications included the removal of the prohibition on indirect commerce--- the carrying trade between France and other countries:--yet advantage even in this commerce was held for the French flag through "flag surtaxes," added to the ordinary customs duties levied upon the merchandise imported into France in foreign bottoms, and by the tonnage charges.[BI] A law of March, 1822, renewed the prohibition against the importation of foreign-built ships.[BI] Early under Napoleon III movements toward the adoption of an economic policy similar to that then established in England were begun, and shortly a succession of radical changes in the maritime code were instituted.[BJ] In 1860 a commercial treaty with England was entered into. In 1861 freedom of access of foreign shipping to the French West Indies was permitted, subject to the payment of special duties varying according to the ports whence the goods were brought, or to which they were imported. Then at length, in 1866, numerous restrictions of the old code were swept away.[BJ] This law of 1866 (May) admitted duty-free all materials, raw or manufactured, including boilers and parts of engines necessary for the construction, rigging, and outfitting of iron or wooden ships; abolished a premium, or bounty, granted by a law of 1841 (May) on all steam engines manufactured in France intended for international navigation; admitted to registration foreign-built and fully equipped ships upon the payment of two francs a ton; abolished all tonnage duties on foreign ships, except such as had been or might be levied for the improvement of certain commercial harbors; abolished the flag surtaxes; opened colonial navigation to foreign ships. The monopoly of the coasting trade alone was retained for French ships.[BK]