Patterson, Robert (1743–1824), mathematician and educator, was born 30 May 1743 at Hillsborough, Co. Down, eldest son among three sons and two daughters of Robert Patterson, presbyterian farmer, and Jane Patterson (née Walker). Educated locally, he displayed a natural talent for mathematics, but financial restraints prevented him from developing it further. At the age of 16 he enlisted in the local militia to defend the coast from French invasion; however, despite being promoted to sergeant he declined a commission in the regular army. Frustrated at his lack of opportunities on the family farm, in 1786 he emigrated to the American colonies, with the intention of having his entire family follow soon after. Settling in Pennsylvania, he found employment as a schoolteacher at Buckingham, Bucks county, and quickly expanded his knowledge of mathematics. A short time later, he was hired to teach navigation in Philadelphia after he impressed in a demonstration of lunar and longitudinal calculations. From his earnings he purchased a small store in Bridgeton, New Jersey, in 1772, and this encouraged him to invite his family to emigrate; they joined him the following year. However, his business soon declined and he jumped at the opportunity to return to teaching; in 1774 he became principal of the Wilmington Academy in Delaware. With the outbreak of the war of independence he enlisted in the revolutionary cause, serving first as a military instructor and then as an adjutant, assistant surgeon, and brigade-major.
In 1779 he was elected professor of mathematics in the University of Pennsylvania, a chair he held for thirty-five years. A friend and correspondent of Thomas Jefferson, he is believed to have helped in the development of the wheel cipher, which was later redeveloped and used by the United States navy during the second world war. In 1805 President Jefferson appointed him director of the federal mint, and he performed his duties with great success till illness forced his retirement. Patterson set a famous prize problem in the second volume of Robert Adrain's Analyst (1808); it was only solved by Nathaniel Bowditch in the fourth volume. The same year he also published The Newtonian system and edited various works of James Ferguson. His final publication was A treatise of practical arithmetic (1819). He also served as vice-provost of the University of Pennsylvania (1810–13) before retiring from teaching in 1814 because of ill-health. In recognition of his scholarship and years of service, in 1819 he was appointed president of the American Philosophical Society and was awarded the degree of LLD by the University of Pennsylvania.
He died 22 July 1824 at his home at 285 Chestnut St., Philadelphia; it was said that he only ever remembered his address because the second digit was the cube of the first and the third was the mean of the other two. He married (1774) Amy Hunter Ewing; they had eight children. His son Robert Maskell Patterson (1787–1854) was also a leading academic at the University of Pennsylvania, succeeding his father as professor of mathematics and natural philosophy and vice-provost; he too was president of the American Philosophical Society (1845–6).