A Brazilian writer said at the First Races Congress: "The cooperation of the _metis_[79] in the advance of Brazil is notorious and far from inconsiderable. They played the chief part during many years in Brazil in the campaign for the abolition of slavery. I could quote celebrated names of more than one of these _metis_ who put themselves at the head of the literary movement. They fought with firmness and intrepidity in the press and on the platform. They faced with courage the gravest perils to which they were exposed in their struggle against the powerful slave owners, who had the protection of a conservative government. They gave evidence of sentiments of patriotism, self-denial, and appreciation during the long campaign in Paraguay, fighting heroically at the boarding of the ships in the naval battle of Riachuelo and in the attacks on the Brazilian army, on numerous occasions in the course of this long South American war. It was owing to their support that the republic was erected on the ruins of the empire."[80] The Dutch brought the first slaves to the North American continent. John Rolfe relates that the last of August, 1619, there came to Virginia "a Dutch man of warre that sold us twenty Negars."[81] This was probably one of the ships of the numerous private Dutch trading companies which early entered into the developed and the lucrative African slave trade. Although the Dutch thus commenced the continental slave trade they did not actually furnish a very large number of slaves to the English colonies outside the West Indies. A small trade had by 1698 brought a few thousand to New York and still fewer to New Jersey. The Dutch found better scope for slaves in Guiana, which they settled in 1616. Sugar cane became the staple crop, but the Negroes early began to revolt and the Dutch brought in East Indian coolies. The slaves were badly treated and the runaways joined the revolted Bush Negroes in the interior. From 1715 to 1775 there was continuous fighting with the Bush Negroes or insurrections, until at last in 1749 a formal treaty between sixteen hundred Negroes and the Dutch was made. Immediately a new group revolted under a Mohammedan, Arabi, and they obtained land and liberty. In 1763 the coast Negroes revolted. They were checked, but made terms and settled in the interior. The Bush Negroes fought against both French and English to save Guiana to the Dutch, but Guiana was eventually divided between the three. The Bush Negroes still maintain their independence and vigor. The French encouraged settlements in the West Indies in the seventeenth century, but at last, finding that French immigrants would not come, they began about 1642 to import Negroes. Owing to wars with England, slaves were supplied by the Dutch and Portuguese, although the Royal Senegal Company held the coveted Asiento from 1701 to 1713.