John de, a celebrated Dutch statesman, was the son of Jacob de Witt, burgomaster of Dort, and was born in 1625. He became well skilled in the civil law, politics, mathematics, and other sciences, and wrote a treatise on the Elements of Curved Lines, published by Francis Schooten. Having taken the degree of doctor of laws, he travelled into foreign courts, where he became esteemed for his genius and prudence. On his return to his native country in 1650, he became pensionary of Dort, then counsellor-pensionary of Holland and West Friesland, intendant and registrar of the fiefs, and keeper of the great seal. He was thus at the head of affairs in Holland; but his opposition to the re-establishment of the office of stadtholder, which he thought a violation of the freedom and independence of the republic, cost him his life when the prince of Orange's party prevailed. He and his brother Cornelius were assassinated by the populace at the Hague in 1674. He was only forty-seven years of age at his death.