The Treaty of Westminster of 1674 was the peace treaty that ended the Third Anglo-Dutch War. Signed by the Dutch Republic and the Kingdom of England, the treaty provided for the return of the colony of New Netherland (now New York) to England and renewed the Treaty of Breda of 1667. The treaty also provided for a mixed commission for the regulation of commerce, particularly in the East Indies.
It was signed on 19 February 1674 Old Style (9 February 1674 New Style) by Charles II of England and ratified by the States General of the Netherlands on 5 March 1674. England was forced to sign the treaty since Parliament would not allow more money to be spent on the war and had become aware of the secret Treaty of Dover in which Charles had promised Louis XIV of France to convert to Catholicism at an opportune moment. The English were dismayed by the unexpected fact that Dutch raiders had managed to capture more English ships than vice versa and that New Amsterdam had been retaken by the Dutch in 1673.
Background
In 1672, England and France had jointly attacked the Dutch Republic. France had occupied a large part of the Republic, but the Anglo-French fleet had been heavily damaged by Lieutenant-Admiral Michiel de Ruyter. In 1673, sustained efforts by the Royal Navy to defeat the Dutch fleet and to land an army on the Dutch coast had failed. Repairs of the English warships proved to be very costly. English mercantile shipping suffered from frequent attacks by Dutch privateers. Meanwhile, France, the English ally in the war, was forced to a gradual withdrawal of its troops from most of the territory of the United Provinces. France threatened to conquer the Spanish Netherlands, which would harm English strategic interests. The war, more or less a private project of Charles and never popular among the English people, now seemed to most to have become a hopeless undertaking.
The English had also been convinced by Dutch propaganda that the war was part of a plot to make their country Roman Catholic again. The commander of the Royal Navy, Prince Rupert of the Rhine, a devout Protestant, had begun to lead a vociferous movement aimed at breaking the French alliance. In late October, Charles asked Parliament for a sufficient war budget for 1674. Its members were extremely critical and denied that it was still necessary to eliminate the Dutch as commercial rivals because English trade had satisfyingly grown between 1667 and 1672. The proposed marriage of the King's brother, the Duke of York, with the Catholic Mary of Modena was lamented. Parliament demanded securities for the defence of the Anglican Church against papism, the disbanding of the standing army (commanded by York) and the removal of pro-French ministers.
When the situation threatened to escalate, Charles, on the advice of the French envoy but against the opinion of the Privy Council, prorogued Parliament. Charles made a last effort to continue the war, even without a war budget. He was promised increased subsidies by King Louis XIV of France. He made plans to capture the regular treasure fleet sailing from the Dutch East Indies. He removed his enemies from office, among them Chancellor Anthony Ashley Cooper, 1st Earl of Shaftesbury, the main opponent of York's marriage. At the same time, Charles tried to lessen fears by reaffirming anti-Catholic measures such as the suspension of the Royal Declaration of Indulgence and by publicising many of his secret treaties with France.
To his dismay, Parliament became more adversarial, now strongly incited by Shaftesbury. Some called for William III of Orange, the stadtholder of Holland and grandson of Charles I of England, to become king if Charles died by excluding the Duke of York. That came as no surprise to William, who had secret dealings with Shaftesbury and many other English politicians. William had agents working for him in England, such as his secretary, Van Rhede. Spain assisted him by threatening to declare war and meanwhile bribing parliamentarians. The States-General had supported the pro-Dutch peace party of Lord Arlington in a more formal manner by making a peace proposal in October and by regularly distributing manifests and declarations in England that explained the official Dutch position and policy. In 1672, England and France had agreed never to conclude a separate peace, but the States now revealed to Charles that they had recently received a peace offer from Louis.
When in late December, General François-Henri de Montmorency, duc de Luxembourg withdrew the bulk of the French occupation army from Maastricht to Namur, Charles lost faith completely and decided to disentangle himself from the entire affair.