Thomas Thacher (May 3, 1850 – July 30, 1919) was an American lawyer. Life Thomas Thacher was born in New Haven, Connecticut on May 3, 1850. He was a descendant of the Rev. Peter Thacher, the rector of St. Edmonds, Salisbury, England; and of his son, Thomas Thacher, who came to America in 1635, settled in Salem, Massachusetts, and later became the first minister of the Old South Church in Boston. His father, Thomas Anthony Thacher, LL D. (Yale BA 1835), was professor of Latin at Yale College from 1842 to 1886, and his mother, Elizabeth (Day) Thacher, was the daughter of Jeremiah Day (Yale BA 1795), president of Yale from 1817 to 1846, and Olivia (Jones) Day. On his mother's side he traced his ancestry to Robert Day, who emigrated from Ipswich, England in 1634, settled in Cambridge, Massachusetts, and in a few years removed to Connecticut and helped to found Hartford. Thomas Thacher prepared for college at the Hopkins Grammar School before attending Yale University. He received a first prize for declamation in Sophomore year. His appointments were a high oration in Junior year and an oration in Senior year, graduating in 1871. He was a member of Phi Beta Kappa, Skull and Bones, and Brothers in Unity. After graduation he taught for a year in the Hopkins Grammar School, and then spent a year in graduate study at Yale University. He entered the Columbia Law School in 1873, and was graduated with the degree of LL.B. in 1875, immediately upon graduation being admitted to the bar of New York, of which he became an active and influential member. His first professional association was with Ashbel Green, then one of the leaders of the New York Bar, with whom he collaborated in the preparation of Brice's Ultra Vires, which became a standard American work on corporation law. After completing this work he was associated with Judge Green in the office of Alexander & Green, and later served as attorney for one of the largest mortgage companies in New York City. On January 1, 1884, he formed the firm of Simpson, Thacher & Barnum (now Simpson, Thacher & Bartlett), with John W. Simpson and William M. Barnum (B A. 1877) as partners. In this, and its successor firms, he was an active partner until his death. Among his partners were Philip G. Bartlett, Yale 1881; his brother, Alfred Beaumont