Three months later the Dutch commander with all his troops left Brazil, and the only fragments remaining to the States General after a tremendous outlay of money and blood were a few islands in the West Indies and a piece of the Guiana country: small return for great effort. Portugal paid eight million florins to the Dutch in settlement of Brazilian differences and agreed to allow Holland free trade with the American colonies in all articles except the precious brazil-wood. The chief results of Dutch occupation of the four capitanias of the north-eastern promontory for twenty-four years were, first, stimulation of world interest in this part of the vast Americas, for the sea-captains who carried Brazilian products for the first time into other parts of Europe than Portugal acted as advance agents of Brazilian commerce: second, scientific investigation into natural products and demonstration of the value of drugs peculiar to this part of South America: third, introduction of better town management systems: fourth, creation of a healthy national spirit in the northern provinces, with lasting effect upon character: and the quickening of colonization in the extreme north. It was not until the Dutch and French settled in Ceará and Maranhão and on the Amazon that serious efforts were made to develop these tropical territories under the equator; the year 1620 witnessed the first arrival of settlers of Portuguese nationality in Maranhão when two hundred families came from the Azores. Another interesting and direct result of the Dutch intervention was the creation of the Companhia do Commercio do Brasil (Commercial Company of Brazil) by the Governor General, intended as a set-off to the Dutch West India Company. It was established in 1650, received monopolies and concessions of a valuable character, and in return was obliged to provide a powerful armed fleet to convoy merchant vessels through enemy-infested seas. The Commercial Company did as a fact render great services to the Brazilians fighting against the Dutch, blockading northern ports while insurgent armies attacked by land.