By the middle of the 17th century the Dutch had built by far the largest mercantile fleet in Europe, with more ships than all the other states combined, and their economy, based substantially on maritime commerce, gave them a dominant position in European trade, especially in the North Sea and Baltic. Furthermore, they had conquered most of Portugal's territories and trading posts in the East Indies and much of Brazil, giving them control over the enormously profitable trade in spices. They were even gaining significant influence over England's trade with her as yet small North American colonies.