Because of this Loevestein-connection (the name of the state prison was also used as an epithet by his Orangist opponents) it was later said of him that he was un oeuf pourri, couvé a Louvestein and he indeed suffered from a weak constitution all his life.

He was twice married, first on 6 October 1652 at The Hague to Agatha van Rijn, and after her death in 1673, on 11 July 1675 at Rijswijk to his cousin Alida de Groot.

When he was ejected from that post as a consequence of the political upheavals that brought the Valckenier-faction to power in 1668, De Witt saw to it that he was appointed Dutch ambassador to Sweden.

It was felt that the defense of the republic was about to collapse, and that the only way to avoid an unconditional surrender was to offer Louis the Generality Lands and a large war indemnity.

However, Louis demanded additional concessions, like the cession of the Nijmegen Quarter of the province of Gelderland, and public toleration of Catholic worship throughout the republic.

His post as Pensionary was taken over by the Orangist Johan Kievit who would shortly play a leading role in the lynching of the De Witt brothers.

[4] Though in exile and disgrace with the new regime of Stadtholder William III De Groot could not resist interfering with diplomatic developments.

He traveled to Cologne (by way of Liège and Aachen) where he offered his valuable services to the Dutch diplomats negotiating peace with the Elector in 1673.