This latter concession, however, the United Provinces obtained from France by the treaty of alliance of 1662, and the commercial treaty signed at the same time with the peace, at Nimiguen, in 1671; confirmed by the treaty of Ryswick, in 1697. The maxim that _free ships_ make _free goods_ was coupled in these treaties with its correlative maxim, _enemy's ships_ make _enemy's goods_. The same concession was obtained by Holland from England in 1668 and 1674, as the price of an alliance between the two countries against the ambitious designs of Louis XIV. In the subsequent war of 1756, a controversy arose between England and Holland, in which it was said, on the one hand, that England had violated the rights of neutral commerce; and on the other, that Holland had not fulfilled the guarantees under which those privileges had been granted. Afterwards, when the American Revolution gave rise to a war between France and Great Britain, the latter power, instead of following the example of her enemy, (who had issued an ordinance prohibiting the seizure of neutral vessels, even when bound to or from enemy ports, unless carrying contraband,) issued an order in council, (March, 1780,) suspending the special stipulations respecting commerce and navigation contained in the Treaty of 1674. This was the crisis of many complaints made by the neutral powers against Great Britain; and, in 1780, the Empress of Russia proclaimed the principles of the Baltic Code of Neutrality, and declared she would maintain them by _force of arms_. This system of armed neutrality contained the following principles. 1. That commerce with the ports and roads of the enemy is free to neutral powers. 2. That the ship covers the cargo. 3. That those merchandizes only be considered as contraband, which are declared to be such by treaties with the belligerent powers, or with one of them. 4. That no place shall be considered as blockaded, till it is surrounded in such a manner by hostile ships that no person can enter it without manifest danger. 5. That these principles shall serve as a basis for decisions concerning the legality of prizes. The principal powers of Europe, as Sweden, Denmark, Prussia, Germany, Holland, France, Spain, Portugal, Naples, and also the United States, acceded to the Russian principles of neutrality. The Court of London answered this declaration by appealing to "the principles generally acknowledged as the Law of Nations, being the only law between powers where no treaties subsist;" and to "the tenor of its different engagements with other powers, where those engagements had altered the primitive law by neutral stipulations, according to the will and convenience of the contracting parties."