At the end of the Middle Ages the dukes of Burgundy, a country that is now part of France, united seventeen areas. Those areas were called the Netherlands. When the daughter of a duke married Maximilian I, Holy Roman Emperor in 1477, the Netherlands became part of Spain. In the 16th century many Dutch people became Protestant. The king of Spain did not like it, he wanted all Dutch to be Roman Catholic. Of course the Dutch people did not like this, and after violent excesses by the Spanish they started a war against Spain in 1568, also for reasons of taxation. The war lasted until 1648, therefore it is called the Eighty Years' War. An important leader of the Dutch in this war was Willem van Oranje (Willem of orange) also called William the Silent.