After he completed his studies in France he became secretary of
Albert Joachimi, ambassador of the
States-General of the Netherlands at the
Court of St James's around 1625. Returned to the Netherlands, he became a member of the Schiedam
vroedschap in 1629 and a few years later
pensionary of that city. As such he represented the city in the
States of Holland and the States-General. In the matter of what has become known as the
Second Northern War, in which the Dutch Republic tried to maintain the
balance of power in the Baltic area, usually siding with Sweden's opponents, especially Denmark, it was Nieupoort's role to manage the Commonwealth, which had a predilection for the Swedish side. He was successful in keeping the Commonwealth out of the war "on the wrong side" for the Dutch. After the
Restoration of king
Charles II of England Nieupoort was recalled by the States-General, as he was deemed to be
persona non grata with Charles. He took up his political work in the Republic again. He was not employed in the negotiations of the
Treaty of Breda (1667) after the
Second Anglo-Dutch War (unlike his colleagues Beverningh and Jongestall). After the murder of Johan and
Cornelis de Witt in August 1672, he was attacked by an Orangist mob in Schiedam and imprisoned, because of his States-Party affiliation. Later, the new stadtholder,
William III of Orange relieved him of all his political offices in the ensuing political
purge. He lived his last years as a private citizen. He died on 2, May 1678 in The Hague. ==Notes and references==