By 1637, the Spanish wrote that the Dutch "In those three settlements of Amacuro, Essequibo and Berbis the have many people... all the Aruacs and Caribs are allied with him", with later reports of the Dutch building forts from Cape North at the Amazon River to the opening of the Orinoco River. In 1639, the Spanish stated that the Dutch in Essequibo "were further protected by 10,000 to 12,000 Caribs in the vicinity of which they frequent, and who are their allies". Captain Groenewegen was recognized as keeping both the Spanish and Portuguese from settling in the area.