[1] In the States of Holland, during these years, the Delft government generally aligned with Amsterdam in opposition to the foreign policy of William III of Orange.

[2] This mission seemingly contributed to convincing Heinsius that the power and politics of Louis XIV were indeed perilous and rightfully opposed by William III.

In early 1685, he departed for England with several other delegates to negotiate difficulties between the Dutch (VOC) and English (EIC) East India Companies.

By the spring of 1686, the commission returned without achieving its goal, but in 1687 he became a member of the board of the Delft chamber of the Dutch East India Company.

The Dutch hoped to create a barrier that would provide the strategic depth needed to protect their commercial and demographic heartlands around Amsterdam against attack from the south.

The Ryswick peace negotiations which ended the Nine Years' War, allowed, among other things, the Dutch to place garrisons in eight Spanish key cities.

[4][1] During the War of the Spanish Succession, Heinsius, along with the Duke of Marlborough and Prince Eugene, formed the triumvirate that, in various respects, governed Europe.

Dutch priorities were to re-establish and strengthen the Barrier fortresses, retain control of the economically vital Scheldt estuary, and gain access to trade in the Spanish Empire.

To relieve the pressure, Marlborough marched up the Rhine, joined forces with Louis of Baden and Prince Eugene, and crossed the Danube on 2 July.

At the Battle of Ramillies, a French army was decisively defeated, leading to a substantial portion of the Spanish Netherlands falling into the hands of the Anglo-Dutch forces.

The sovereignty of Charles was theoretically recognized, yet governance would be administered by a Council of State comprising Belgians, acting on his behalf under the regency of the Maritime Powers.

The immediate threat to the Republic had diminished, sparking hope in Paris and anxiety in London and Vienna that Heinsius might seek a separate peace.

Allied defeats in Spain, high corn prices from poor harvests and heavy land taxes had fuelled public dissatisfaction in Britain against the Godolphin–Marlborough ministry.

In response, Queen Anne dismissed the Whig Junto, including Marlborough, and in their place a Tory ministry led by Robert Harley came to power.

This approach solidified after the death of Joseph I, Holy Roman Emperor in 1711, as the Tories perceived that allowing Charles VI to unify Habsburg territories in Austria and Spain was an unappealing alternative.

France and Bourbon Spain acknowledged British control over Gibraltar and Menorca along with the granting of the Asiento de Negros and other mercantile privileges to Britain, leading to the preliminaries of peace being signed in London on 8 October.

The Dutch and Austrians, who were dismayed by Marlborough's dismissal and outraged by the Harley ministry's negotiation with France, decided to continue fighting against the French on their own.

[13] These events, including being repeatedly reproached by other Dutch officials in 1712, severely shook Heinsius' authority and self-esteem, and rumours abounded that he intended to resign.

This proved to be untrue, but the Jacobite rising of 1715 in the next year forced the British to back the Dutch, resulting in the ongoing negotiations being concluded to the satisfaction of both sides.

[1] Heinsius and Marlborough together filled King William's place, with less authority, but far greater success.Heinsius held the post of Grand Pensionary for over 31 years, longer than most of his predecessors and successors, except for Johan van Oldenbarnevelt.

[1] Amidst Heinsius' widely acknowledged skills - keen intellect, sound judgment, extensive knowledge, tactfulness, great diplomatic finesse, tireless diligence, and unblemished integrity - lay a characteristic that sometimes hindered him: his humility.

[1] Jean Baptiste Colbert, Marquis of Torcy, a French diplomat, who negotiated some of the most important treaties towards the end of Louis XIV's reign, describes Heinsius as a consummate man in affairs, of a reserved manner, polite in conversation, never harsh and seldom heated in debate.

His demeanor, was accommodating; no ostentation in his household; his staff comprised a secretary, a coachman, a footman, a maid, not indicating the power of a prime minister.he was not accused of finding pleasure in the consideration brought by the continuation of war to prolong it, nor of any personal interest.