a Dutch political figure. He married Anna Weytsen, lady of Brandwijk and Gijbeland, in Delft in 1608. After the execution of his father in 1619, Reinier conspired with his brother Willem van Oldenbarnevelt and amongst others the Remonstrant preacher Hendrick Danielsz Slatius to assassinate stadtholder Maurice of Orange. The assassination attempt failed however, and Reinier van Oldenbarnevelt was beheaded in 1623 in The Hague (as his father had been) for financial complicity in the conspiracy to assassinate prince Maurice.
