Norman Williams and John Leverett Thompson founded what would become Sidley Austin LLP in 1866, and some of the firm’s earliest clients were George M. Pullman, Mary Todd Lincoln and Western Union Telegraph Company. After many years and name changes, the firm became known as Sidley Austin LLP in 2006. The general practice law firm has headquarters in Chicago and more than 2,000 legal professionals across 20 offices in the U.S., Europe and Asia. Sidley Austin LLP attorneys serve clients in several legal disciplines within corporate and finance, employment, tax, and government affairs. The firm received a 100% score from the Human Rights Campaign Foundation's Corporate Equality Index in 2021.