The Republic = Became a little bit stronger
1. More money (thanks to increased trade and industry) -> Dutch can pay their own mercenaries
2. Allies (=Bondgenoten) (ENG and FRA, officially recognised The Dutch Republic and promised to fight against Spain alongside them
3. Maurits proves to be a good military commander, who led Dutch armies to more victories against Spanish army, because he brought more discipline to the Dutch army.
4. Spain fought a lot of wars at the same time. Therefore,they could not always give all attention to their fight against The Netherlands.