The national flag of the Netherlands is a tricolour flag. The colors are red (bright vermilion), white (silver), and blue (cobalt blue). The first Stadtholder, or ruler, of the Dutch Republic was William of Orange, who joined with Dutch nationalists and led the struggle for independence from Spain. Partly out of respect for him, the first flag adopted by the Dutch was originally orange, white, and blue. The orange dye was particularly unstable and tended to turn red after a while, so in the mid-17th century, red was made the official color. The flag has flown since then. As the first revolutionary flag, it has had an influence throughout the world. Until about 1800, in the case of both the orange- and the red-striped versions, the number of stripes and their order frequently varied.