The following data is extracted from A Standard History of Kansas and Kansans.
Sidney Clarke, one of the early members of Congress from Kansas, was born at Southbridge, Massachusetts. October 16. 1831, and in his early manhood published and edited a weekly newspaper which he had founded in his native town. He became an active free-soil advocate, supported Freemont in 1856. and three years later, upon the advice of his physician, went west and located at Lawrence. He hecame an ardent supporter of the radical wing of the free-state party, and in 1862 was elected to the State Legislature. The following year President Lincoln appointed him adjutant general of volunteers, and he was assigned to duty as acting assistant provost marshal general for the District of Kansas, Nebraska, Colorado and Dakota, with headquarters at Fort Leavenworth. The same year he was made chairman of the Republican State Committee, a position previously held by the ablest of the old frcestate leaders. In 1864 he was elected to Congress and re-elected for two succseding terms, serving as chairman of the House Committee on Indian Affairs and a member of the Pacific Railroad Commission. He participated in all the leading conflicts which made the history of Congress memorable during the six years he was a member of that body. The defeat of the Osage Indian treaty and the passage of the Clarke bill saved to Kansas much of her public school lands. During his three terms in Congress Mr. Clarke was the only representative from Kansas and he referred proudly to himself as "the sole representative of my imperial state." He was in Congress at the time of the assassination of President Lincoln, of whom he was a close friend, and was placed on the committee that accompanied the body to its last resting place. He was defeated for election to Congress in 1870, but was elected to the State Legislature in 1878 and made speaker of the House. In 1898 he removed to Oklahoma, and few men had a more powerful hand in shaping the destinies of the new state. Thereafter his record is identified with that section of the country, his death occurring at Oklahoma City, June 19, 1909.
Source: A Standard History of Kansas and Kansans