Jan Van Olden Barneveldt, grand pensionary of Holland, born at Amersfoort, Sept. 14, 1547, beheaded at the Hague, May 13, 1619. After studying law and divinity five years he began to practise law at the Hague in 1569, and soon became known as an able lawyer. He served in the army against the Spaniards, and was present at the siege of Haarlem in 1573. In 1585, after the death of William of Orange, he headed a deputation which offered the sovereignty of the Dutch provinces to Queen Elizabeth. The queen refused the offer, but sent a force under the earl of Leicester to their assistance. Barneveldt was soon afterward appointed advocate general or grand pensionary of Holland and West Friesland, and became leader of the republican party which favored subordinating the stadtholder to the legislature. He opposed the influence which the earl of Leicester was gaining, and in order to limit his military power had the dignity of stadtholder conferred on the young Prince Maurice, son of William of Orange. In 1603 he was one of an embassy to James I., and succeeded in obtaining the secret aid of England and France against Spain. In the religious strife between the Gomarists and Arminians, which began in 1604 and soon included all the clergy and laity of Holland, Barneveldt, who with most of the eminent scholars and statesmen of the country favored the more liberal views of the Arminians, endeavored to reconcile the two factions, now upon the point of war, by a conference of ecclesiastics, which resulted in a declaration of general toleration on the disputed points.

In this the states concurred, and in 1614 an edict was issued enjoining peace. But Maurice, now Barneveldt's great rival, being at the head of the military party which had favored a prosecution of the war with Spain, while Barneveldt had in 1609 concluded a truce of 12 years, procured the summoning of the council of Dort, Nov. 13, 1618, which condemned entirely the Arminian doctrines. Barneveldt and his friend Grotius had already been arrested at the instigation of Maurice in the beginning of that year. His trial soon followed the decision of the synod, and was a mere farce, it having been already determined that he should die. He was found guilty, among other things, of "having brought the church of God into trouble," and was beheaded. As grand pensionary, which office he held until the year before his death, he conducted through peace and war the affairs of the commonwealth with great ability; and in the conflicts of religious factions he advocated the most enlightened measures of toleration and freedom.

His two sons formed a plot to avenge his death by assassinating Maurice. The conspiracy being detected, one of them escaped, while the other was seized and executed.