This is the war fought between Catholic Spain and the Protestant Netherlands which resulted in the independence of the Netherlands from Spain, the separation of the Southern part of the Netherlands (Flanders) from the Northern part. The result was the formation of the United Provinces of the Netherlands, the Dutch Republic.
First regular armies, mostly mercenaries, under the orders of Prince William I of Orange attempted and failed to invade the Dutch provinces.
But there were also the foreign based irregular land and sea forces of the Geuzen, fanatical Protestants who raided the provinces and by the end of 1573 had captured and by force converted to Protestantism the provinces of Holland and Zeeland. Then the other provinces joined them in the revolution against Spain and they formed a general union.
The Catholic Southern part of the Netherlands, in particular the Catholic Walloon provinces seceeded from the Dutch Union in 1577. None of them wanted to be part of the Spanish Empire either but by 1588 the Spanish had regained control over them. By now Spain was engaged in war also against France and England and this made a Dutch counteroffensive possible.
During the 12 Years' Truce the Dutch tried hard to secure their borders. When fighting resumed in 1621 this revolt had become part of a more general conflict known as the Thirty Years' War.
An alliance of the French and the Dutch came into being in 1635 and this led to the French conquest of the Walloon provinces and sustained French attacks against Flanders.
In 1648 the Spanish Republic, now worried about the growing power of France, concluded a separate peace with the Netherlands. This came to be known as the Treaty of Munster by which Spain recognized the independence of the Dutch.
All that you can find in the history books. What those books hardly ever touch on is the misery all this caused for the common man caught between unruly armies and irregular forces all of whom had to take mostly from civilians everything they needed to survive.
In 1583 for instance the dikes were pierced in our Meetjesland and thousands of hectares of good land taken from the sea disappeared once again under the salty water.
After such a long period of conflict and destruction many many farms lay ruined and abandoned and many many people had fled the region never to return.