Arnold, Isaac Newton (1813-1884) Born in Hartwick, New York, Arnold joined the Illinois bar in 1835. He moved to Chicago the following year, where he became the first Clerk of Chicago and, in 1837, started a very successful law partnership with M.D. Ogden. He also served on the first CPS Board of Inspectors, in the Illinois legislature, and in the United States House of Representatives. A staunch opponent of slavery, Arnold was a friend of Abraham Lincoln and the author of such important biographical works as The Life of Abraham Lincoln and The Life of Benedict Arnold.