On 30 January 1648, after a war that had lasted eighty years, the Republic and Spain signed a peace in the Westphalian city of Münster. A few months later, on 5 June 1648, the peace was officially proclaimed. The King of Spain, Philip IV, accepted the outcome of the preceding period: he renounced his claim on the northern provinces of the Netherlands and recognized the Republic as an independent state.
In 1621, after the Twelve Years' Truce had come to an end, the conflict broke out once more, but it was no more a matter of rebellion against de jure Spanish rule. Countries like France and England had recognized the Republic and the new state had managed to consolidate its internal affairs. In those years, the Republic fought against Spain all over the world, entering into alliances with other countries to do so. In the Netherlands, battles were fought particularly in the east and the south. Led by Frederick Henry, the youngest son of William of Orange, the ‘Father of the Nation', the Republic's troops conquered a number of major cities in the years after 1625: Groenlo in 1627, Den Bosch in 1629, Maastricht in 1632, Breda in 1637, and Hulst in 1645. In signing the Treaty of Münster, Spain recognized these conquests, thus establishing the frontiers of the Republic. Prince Frederick Henry did not live to experience the dawn of peace with Spain: he had died in 1647 at the age of 63 years.
The other side of the coin was that the northern and the southern provinces of the Low Countries were now definitely separated from each other: two nations, different religions and different societies. Each went its own way and although some attempts were made later to reunite them, the differences had become so great that all these attempts failed.
Peace was celebrated with great enthusiasm in many parts of the country: peace is always good for trade. Furthermore, Spain had accepted the firm foothold the Dutch had gained in Asia, Africa and America. The protracted war had also cost a huge amount of money through the years. The city of Amsterdam and North Holland, the richest of the provinces, were particularly pleased with the peace since they had borne the heaviest financial burden during the years of struggle. In June 1648, work for the construction of a new city hall was begun in Amsterdam. The building was to symbolize not only the city's vast power and immense riches, but also the newly won peace.
Other cities and provinces, however, feared that their economy would suffer greatly from peace. Zeeland, for one, protested at length: after all, commandeering Spanish ships was an extremely lucrative business. In Utrecht, the objections were of a more religious nature: did not the Treaty imply that the southern provinces were lost to the doctrine of Calvin? Frederick Henry's son, William II, did not rejoice either. As commander in chief of the army and navy he owed his power and influence to the continuation of hostilities. Finally, the Republic's most important ally, France, was not exactly happy about the peace. France had not lost its long-standing interest in part of the southern provinces. Since the Republic did not wield any military power there now, these provinces had to carry on the war against Spain on their own.
Still, the Treaty of Münster was an official endorsement for a situation that already existed. At the time, the Republic had already been a major European power for decades. From an economic and cultural point of view, the country was at the height of its Golden Age. The art of painting, architecture, literature, and music flourished as never before, giving the Republic its own special identity. Dutch warships and merchant marine vessels had ruled the seas for half a century and the Dutch colors flew from Japan to North America. The fact that many of the Republic's own citizens opposed the peace demonstrates how powerful they felt.