§ 44. Before the nineteenth century blockade was only known as a measure between belligerents in time of war. It was not until the second quarter of the nineteenth century that the first case occurred of a so-called pacific blockade--that is, a blockade during time of peace--as a compulsive means of settling international differences; and all such cases are either cases of intervention or of reprisals.[46] The first case, one of intervention, happened in 1827, when, during the Greek insurrection, Great Britain, France, and Russia intervened in the interest of the independence of Greece and blockaded those parts of the Greek coast which were occupied by Turkish troops. Although this blockade led to the battle of Navarino, in which the Turkish fleet was destroyed, the Powers maintained, nevertheless, that they were not at war with Turkey. In 1831, France blockaded the Tagus as an act of reprisal for the purpose of exacting redress from Portugal for injuries sustained by French subjects. Great Britain and France, exercising intervention for the purpose of making Holland consent to the independence of revolting Belgium, blockaded in 1833 the coast of Holland. In 1838, France blockaded the ports of Mexico as an act of reprisal, but Mexico declared war against France in answer to this pacific blockade. Likewise as an act of reprisal, and in the same year, France blockaded the ports of Argentina; and in 1845, conjointly with Great Britain, France blockaded the ports of Argentina a second time. In 1850, in the course of her differences with Greece on account of the case of Don Pacifico,[47] Great Britain blockaded the Greek ports, but for Greek vessels only. Another case of intervention was the pacific blockade instituted in 1860 by Sardinia, in aid of an insurrection against the then Sicilian ports of Messina and Gaeta, but the following year saw the conversion of the pacific blockade into a war blockade. In 1862 Great Britain by way of reprisal for the plundering of a wrecked British merchantman, blockaded the Brazilian port of Rio de Janeiro. The blockade of the island of Formosa by France during her differences with China in 1884 and that of the port of Menam by France during her differences with Siam in 1893 are likewise cases of reprisals. On the other hand, cases of intervention are the blockade of the Greek coast in 1886 by Great Britain, Austria-Hungary, Germany, Italy, and Russia, for the purpose of preventing Greece from making war against Turkey; and further, the blockade of the island of Crete in 1897 by the united Powers. The last case occurred in 1902, when Great Britain, Germany, and Italy blockaded, by way of reprisal, the coast of Venezuela.[48]