Frederick Theodore Frelinghuysen (August 4, 1817May 20, 1885) was an American lawyer and politician from New Jersey who served as a U.S. Senator and later as United States Secretary of State under President Chester A. Arthur. Early life and education Frelinghuysen was born in Millstone, New Jersey, to Frederick Frelinghuysen (1788–1820) and Mary Dumont. His father died when he was just three years old, and he was adopted by his uncle, Theodore Frelinghuysen (1787–1862). His grandfather, Frederick Frelinghuysen (1753–1804), was an eminent lawyer, one of the framers of the first New Jersey Constitution, a soldier in the American Revolutionary War, a member (1778–1779 and 1782–1783) of the Continental Congress from New Jersey, and from 1793 to 1796 a member of the United States Senate. His uncle, Theodore Frelinghuysen, was Attorney General of New Jersey from 1817 to 1829, was a U.S. Senator from New Jersey from 1829 to 1835, was the Whig candidate for Vice President of the United States on the Henry Clay ticket in the 1844 Presidential election, and was Chancellor of New York University from 1839 until 1850 and president of Rutgers College from 1850 to 1862. Frelinghuysen graduated from Rutgers College in 1836, and studied law in Newark with his uncle, to whose practice he succeeded in 1839, after he was admitted to the bar. Career Following his admission to the bar, he became attorney for the Central Railroad of New Jersey, the Morris Canal and Banking Company and other corporations. Political career According to The New York Times, Frelinghuysen was a member of the Whig Party until joining the Republican Party upon its inception. He was also crucial in establishing New Jersey's state GOP. During the American Civil War, Frelinghuysen was active in public office rather than joining the Union Army. He was a delegate in 1861 to the Peace Congress, and appointed Attorney General of New Jersey by Governor Charles S. Olden that year to serve in the post until 1867. Frelinghuysen was encouraged by some to run for governor in 1862, though declined. Frelinghuysen was a delegate to the 1860 Republican National Convention from New Jersey and from 1861 to 1867 was Attorney General of New Jersey. He was a delegate to the Peace conference of 1861 in Washington, and in 1866 was appointed by the Governor of New Jersey, as a Republican, to fill a vacancy in the United States Senate. In