Proclaimed in 1651, the Navigation Act is one in a long series of decrees by which the English government attempted to protect its own commercial interests. The Act under Oliver Cromwell provided that no countries would be allowed to ship to England goods that they had not produced themselves. Import was permitted only on producing countries’ own or English ships, and only English ships were to transport products between England and its colonies. This act was, of course, directed largely against Dutch shipping. Hollandconsidered the proclamation to be a casus belli for the First and Second Anglo-Dutch Wars, of 1652–1654 and 1665–1667. With the Treaty of Breda in 1667, the Navigation Act was to some extent mitigated, but it was not to be repealed until the era of free trade in 1849.
Historical Dictionary of the Netherlands. EdwART. 2012.