Henri de Fleury de Coulan

This may explain why Buat became attached to the court of young William III in the early 1660s, while still commanding the regiment, despite the fact that, officially, the Dutch government of the day frowned on the aspirations of the Orangists.

In 1659, he was a volunteer with de Ruyter's expedition to the Sound in the Northern Wars, and at Kerteminde, Buat distinguished himself during the landing of Dutch troops on the Danish island of Funen.

In October 1665, during the Second Anglo-Dutch War he was appointed by the States of Holland to accompany the cavalry of the French army in its campaign against Munster, to assist it finding accommodation and provisions.

Sylvius was acting on behalf of Lord Arlington, a minister of Charles II, and this correspondence was originally a diplomatic "back channel" between the Dutch and English governments to explore possibilities of peace.

They plotted to bring about an Orangist coup d'état in the Republic, which would overthrow the de Witt regime, restore the stadtholderate, end the war, and renew Anglo-Dutch friendship.

[20] However, another account suggests that de Witt wished to use Buat to entrap those opposed to him, such as Kievet and van der Horst, and to discredit the Orangists generally.

[22] In the criminal procedures that followed it transpired that, besides Buat, only two Rotterdam regents, Johan Kievit and Ewout van der Horst, had sufficiently compromised themselves to be charged.

This in itself was controversial, as the asserted treason was against the Generality, so that the Hoge Raad van Holland en Zeeland (the federal supreme court) might have been more appropriate.

[25] In addition, he was convicted after one of the judges who might have voted in his favor (Jacob van der Graeff, the father of the would-be assassin of Johan de Witt, who was executed in 1672), had been forced to recuse himself, so altering the balance in the court.