The _Mare Liberum_ of Grotius was published anonymously at Leyden, Holland, in March 1609.[616] As the title declares, the author’s object was to assert the right of the Dutch to trade with the Indies, and to combat the pretensions of the Portuguese to a monopoly of navigation and commerce in those regions; but the genesis of the book has only been recently made known. At the end of the sixteenth century, when the commerce of the United Provinces was expanding in all directions, the Dutch merchants resolved to share in the lucrative trade with the far east. Having failed to open up a passage to the Indies by the north-east, they boldly sailed thither by the Cape of Good Hope, in 1595, through the seas and to the regions which Portugal claimed for herself. Encouraged by success, other trading voyages by the same route were undertaken almost every year. A United Dutch East India Company was formed in 1602, and the States-General decided to maintain their rights to the trade by force. The disputes and conflicts with the Portuguese which followed were soon brought to a head by the action of the redoubtable Jacob van Heemskerk in attacking and seizing Portuguese ships.[617] The valuable booty taken from the Portuguese was brought to Holland in 1604 and 1605, and caused much searching of heart among the shareholders of the company. Many were gratified by the spoil, but others of much influence, moved by conscientious scruples or good policy, refused to share in it, and they threatened to separate themselves from the company and form a rival association to carry on peaceful trade under the protection of the King of France. It was about this time that Grotius, incited by the condition of affairs, began to write a treatise with the object of encouraging his countrymen to resist the claims of the Portuguese by force. In a tract written about 1614 to vindicate _Mare Liberum_ against the attack of the Scotch lawyer, Welwood--which was not published, and the existence of which was unknown till about forty years ago--he says that some years earlier, perceiving the great importance of the East Indian trade for the Netherlands, and that it could only be made secure by armed resistance to the Portuguese, he had written a book in which he explained the law of war and spoil; and in order to rouse the popular mind he gave an account of the ill-treatment of the Dutch in the East Indies at the hands of the Portuguese.[618] Grotius was then only a little over twenty years of age, and it enhances our sense of the precocity and fertility of his genius to learn that _Mare Liberum_ was only one chapter (the twelfth) of this treatise. The treatise itself was not published by Grotius; but in 1608, during the negotiations with Spain which ended in the truce of Antwerp, on (March 30)/(April 9), 1609, the Spaniards demanded that the Dutch should relinquish the trade with the West Indies and also with the East Indies (Portugal being then