A royal warrant of 6 November 1663, regulated the use of the triple-tailed flag, to be used only as a state flag and military ensign. According to the same royal warrant, merchant ships were only allowed to fly square-cut city flags in their respective provincial colours. In practice, however, the merchant fleet began using a square-cut civil ensign of the state flag. In a government instruction of ship building of 1730, this civil ensign should have the same proportions and colors as the state flag, with the notable difference of being square-cut. In 1756, the use of pennants by private ships was prohibited.