I'm Dutch myself and i just made a exam about that subject so il answer you're question

First of the dutch republic was more like a federation, you had 8 normal provinces and 2 General provinces (which had slightly more autonomy) Thats why the official name of the dutch republic was vereenigde provincies der nederlanden or United provinces of the netherlands.

You know what, here is a picture of what my schoolbook has to say, fully english, because bilangual schools are awesome http://imgur.com/dbnkS7C