I read The Black Tulip by Dumas recently, and this not-so-accurate telling of the murders piqued my interest.
I don't fully understand the difference in principles between the followers of William of Orange and the republicans.
It seems as though the de Witts weren't that evil so the uprising threw me off.
Political structure
Dutch politics of this era was very complicated. Each province was sovereign but had delegated some authority regarding matters of defense and international relations to the Republic. Each province was ruled by Staten ('States'; for example Staten van Zeeland, 'States of Zeeland') which consisted of representatives of the nobility and cities of the province. Every representative in the States was equal, but in some provinces the nobility were dominant and in other the cities. Since all members were equal, the meetings of the States were prepared and presided by someone appointed by the States, called raadpensionaris ('pensionary of council') in Holland. Think of him as the highest civil servant of the province. The States also appointed a stadtholder for their province, who acted as an executive for the province (though sovereignty remained with the States). The stadtholder usually was someone from the House of Orange-Nassau, often the Prince of Orange, and several provinces might have the same stadtholder.
The States of each province sent representatives to the Staten-Generaal ('States-General'), which was the executive body of the United Provinces. Each of the seven provinces had one vote in the States-General. The States-General determined foreign policy and defense for the Republic (they also had responsibility for those lands controlled by the Republic which were not part of any represented province). In this capacity, the States-General appointed a captain-general and an admiral-general, commanding respectively the army and the navy of the Republic. Usually they would choose as captain-general the person which was the stadtholder of Holland, which usually was the Prince of Orange.
Cornelis de Witt
Cornelis de Witt was a leading politician of the city Dordrecht, which was the oldest and most influential city of Holland. As representative from Dordrecht, Cornelis was a member of the States of Holland. Furthermore, he acted as 'deputy in the field' for the States-General, often accompanying armies or navies. Bearing such responsibilities made him subject to scrutiny and criticism. For instance, in 1664 the prince-bishop of Münster invaded the east of the country. The Dutch army was commanded by Johan Maurits of Nassau-Siegen, and Cornelis de Witt was present as deputy in the field, advising the commander. The initial response to the invasion was to withdraw behind the IJssel river, a move which was authorised by Cornelis de Witt. This left much of the east of the country open, and the failure to protect this part of the country damaged the standing of De Witt and the entire States of Holland.
Johan de Witt
Johan de Witt was an even more prominent politician than Cornelis. As raadpensionaris of the States of Holland, he effectively controlled the political decision-making. With Holland being the most important province of the Republic, his control over the States of Holland granted him much influence in the States-General (incidentally, the States-General held their meetings at the Binnenhof in the Hague, mere meters from where the States of Holland held their meetings). Johan de Witt disliked the influence the House of Orange-Nassau had in Dutch politics and did everything to reduce their influence. In 1650, when Holland refused to continue paying for the large army, demanding its size be reduced, stadtholder Willem II (Prince of Orange) imprisoned six leading politicians and marched the army to Amsterdam. The States of Holland gave in, but later that year the Prince died of illness and Johan de Witt (then just a representative) and the States of Holland seized the opportunity.
The Prince's son was born only after his death, so he wasn't capable of being stadtholder. Instead of appointing a regent or choosing someone else as stadtholder (Frisian stadtholder William Frederick, Prince of Nassau-Dietz for instance), the States of Holland elected not to appoint a stadtholder. The States took over the stadtholder's powers within the province, while leaving the appointment of magistrates (usually a task of the stadtholder) to the cities themselves. This was the start of the 'First Stadtholderless Period' lasting until 1672 (note that this means that Holland did not have a stadtholder; other provinces at various times did have one).
Johan de Witt soon was appointed raadpensionaris and became the most influential politician in the Republic. During the peace negotiations at the end of First Anglo-Dutch War, one condition which was discussed was that the Dutch would never appoint an Orange as stadtholder or captain-general. The States-General disagreed with this condition so it was not included in the peace treaty. Johan de Witt however did give the English the secret assurance that the States of Holland would pass an act to that effect (for Holland alone). This Act of Exclusion led to popular outrage and was constitutionally questionable, but De Witt's political and rhetorical skill led to the other provinces and States-General accepting it. As Jonathan Israel put it:
De Witt had survived the Orangist surge of 1652-3, carried the Exclusion, and made peace with England, without making any concession to England's maritime and colonial interests. The episode was triumph for De Witt and Holland's sense of purpose, and solidarity. Nevertheless, it left a bad taste in the mouth of the public. (p.726)
The end of the First Stadtholderless Period
De Witt continued to be the most influential politician for almost two decades, his policies being guided by the idea of Ware Vrijheid ('True Freedom'). True Freedom entailed a rejection of Princes and other rulers, along with their tendencies to waste money and to desire territorial expansion at great cost. Instead, De Witt championed government by the people (read: well-off regents) and sovereignty for the provinces (read: Holland) over the States-General. True freedom mean being your own master over your own soil and your own city. In 1667 the States of Holland passed the 'Perpetual Edict', abolishing the stadholderate entirely, separating the captaincy-general from the stadholderate of other provinces, and formally transferring the powers of the stadholder to the States. The problem with this was that a large section of the populace actually liked the House of Orange. Another problem was that in combatting the waste of money, the army was greatly reduced and ill-equiped. All this backfired in 1672.
In 1672, a coalition of England, France, Munster, and Cologne attacked the Dutch Republic. While France attacked with the largest army in Europe from the south, Munster and Cologne attacked from the east. In a matter of weeks, three of the seven provinces as well as most of the Generaliteitslanden ('Generality Lands', areas controlled by the States-General) were overrun. On sea, Dutch admiral De Ruyter and his advisor Cornelis de Witt (yes, the one this question is about) decided the attack the English fleet before the French fleet could join them. They were too late, but attacked anyway. The Dutch achieved a victory, preventing the English from attacking the Republic from the sea. The situation on land was dire though, and the States of Holland and the States-General decided to withdraw behind the so-called Water Line - a series of defences in inundated land, protecting Holland and parts of Utrecht (but mostly Holland). Utrecht fell to the French, and just Holland and Zeeland remained under control of the Republic.
The States of Holland, acting against Johan de Witt's advice, opened negotiations with France and England. At the end of June a vote passed in the States General, offering all of the Generality Lands and a large indemnity to King Louis of France. Louis expected more though and rejected the terms. The Dutch populace meanwhile demanded the reinstatement of the Prince of Orange as stadtholder. Holland had reluctantly agreed to have the Prince of Orange as temporary captain-general earlier in the year, but appointing him as stadtholder would mean a renounciation of the Perpetual Edict. On July 2 Zeeland made the Prince of Orange their stadholder. This was significant because traditionally Zeeland was the closest political ally of Holland. The next day the States of Holland set aside the Perpetual Edict and also made the Prince of Orange their stadtholder. The stadtholder decided to end the negotiations and continue the war.
The 'trial' of Cornelis De Witt
On June 21st an assasination attempt was made on Johan de Witt. While walking from his work to his home, he was stabbed several times by four assailants. He survived but ceased playing an active role in the decision-making from then on. With the Prince of Orange as stadtholder again, his political ideals in shatters, and the public blaming him for the dire situation the Republic was in, Johan tendered his resignation as raadpensionaris on August 4.
His brother Cornelis was accused of plotting an attempt against the life of the Prince of Orange. Though his accusation was made by an untrustworthy individual, Cornelis was imprisoned in The Hague. There he was tortured, but he did not confess. On August 20 judges told Cornelis that he would be banished and would receive a fine. Upon hearing of the verdict against his brother, Johan - who lived nearby and was still recovering from his wounds - made his way to the prison. There he joined his brother for a meal, while outside a mob gathered.