The Dutch Republic — officially known as the Republic of the Seven United Netherlands, the Republic of the United Netherlands, or the Republic of the Seven United Provinces— was a republic in Europe existing from 1581 to 1795, preceding the modern Kingdom of the Netherlands. Alternative names include United Provinces.
The independence of the Dutch Republic was formally recognized in 1648, as part of the Peace of Westphalia.
Dutch Republic in 1632
During the Thirty Years' War, the Dutch Republic (also known as the United Provinces) was devastated by Spanish forces led by Don Fernando after the Dutch fleet was nearly destroyed by the newly created League of Ostend.
The Dutch Republic effectively ended as a de facto independent state after a peace agreement was reached between Don Fernando and Fredrick Hendrik. This agreement officially united the Netherlands into what became a third Habsburg kingdom, with Don Fernando and Maria Anna of Austria as its rulers. However, one of the terms of the agreement was that the Republic's institutions would effectively remain in place.
By doing so, it will prevent the independence of Belgium and Luxembourg in OTL
Under Don Fernando, attempts have been made to strengthen the Netherland's relations with both the USE and Austria-Hungary
King Fernando has also ordered the building of civilian planes to promote trade (and to serve as bombers should Spain have any ideas of invading again)