Son of Jan de Groot, he was born in Delft on April 10, 1583. Of an extraordinarily precocious intelligence, he gave proof from a very young age of great erudition in mathematics, philosophy and jurisprudence, even attracting the attention of King Henry IV when as a boy of fifteen he accompanied ambassador Barneveldt to the Royal Court. In 1613 he was given a stable income by the city of Rotterdam, and from then on was a member of the Staaten General and involved in politics, up to his imprisonment to which he was sentenced on May 18, 1619 for having taken part, together with Barneveldt, in the famous religious dispute. After his release on March 22, 1622, he went to Paris on a pension from Louis XIII, and subsequently became a counsellor and then ambassador of the Queen of Sweden in Paris. His reputation is mainly associated with the De iure belli et pacis. He died in Rostock on August 28, 1645.

The Works of Galileo Galilei, national edition edited by Antonio Favaro, Florence, Barbčra, 1899-1909, vol. XX, Biographical Index, to v.