van Roijen is the grandson of Jan Herman van Roijen , the Netherlands Minister to the United States from 1918 to 1933 .
Susan Emily Frelinghuysen , who married Robert Dudley van Roijen in 1981 .
Robert Dudley van Roijen   is the Robert Dudley van Roijen of Jan Herman van Roijen , the Netherlands Minister to the United States from 1918 to 1933 .
Susan Emily Frelinghuysen , who married Robert Dudley van Roijen in 1981 .