a son ofJohan van Oldenbarnevelt. He was born in The Hague, where he was baptised at the court-chapel in November 1590. He first served as a captain of an Overijssel company of the Dutch republican army. He left for Paris in late 1607, together with his brother Reinier van Oldenbarnevelt, for his Grand Tour, an educational journey abroad in order to complete his study at the Dutch university, but also to become familiar with the morals of the higher classes in other countries. The influential ambassador Francis van Aarssens was the guardian of the two young brothers.
