Peter Hood Ballantine Frelinghuysen Jr. was born in New York City on Jan. 17, 1916. His father was a banker whose Dutch forebears settled in Somerset County in the 18th century. His mother was the former Adaline Havemeyer. After graduating from Princeton University and, in 1941, from Yale Law School, Mr. Frelinghuysen served in naval intelligence during World War II. He then did postgraduate work in history at Columbia University and was in the investment business in the city before running for Congress in 1952. He married Beatrice Sterling Procter, a descendant of a founder of Procter & Gamble, in 1940. She died in 1996. After leaving Congress, Mr. Frelinghuysen was active in civic affairs and served on the boards of the Metropolitan Museum of Art and the New York Botanical Garden, among other institutions. In addition to his sons Rodney and Peter, Mr. Frelinghuysen is survived by another son, Frederick; two daughters, Beatrice Frelinghuysen van Roijen and Adaline H. Frelinghuysen; 13 grandchildren; and 9 great-grandchildren. Mr. Frelinghuysen’s pride in his political lineage is evident in his entry in the Biographical Directory of the United States Congress. The first thing it states after his name: “Cousin of Joseph Sherman Frelinghuysen, great-grandson of Frederick T. Frelinghuysen, great-great-nephew of Theodore Frelinghuysen, and great-great-great-grandson of Frederick Frelinghuysen” — the four senators in the family tree.