John Pope Cook John Pope Cook ( June 12 , 1825 – October 13 , 1910 ) was an Illinois politician and a general in the Union Army during the American Civil War . He served in the Western Theater and played a prominent role in securing the Union victory at the Battle of Fort Donelson , helping to force the surrender of the defenders . Early life . Cook was born in Belleville , Illinois , to a well connected political family . His maternal grandfather , Ninian Edwards , was a United States Senator and the Governor of Illinois . His father was Daniel Pope Cook , who was a member of the United States House of Representatives at the time . Following Daniel ' s untimely death at the age of 33 , his widow , Julia Catherine Edwards Cook , moved with their only child , John , back to Belleville , where she died three years later , leaving Cook as an orphan . Cook received a good education and entered the practice of law . He was elected mayor of Springfield , Illinois , in 1855 . Cook was the captain and commander of a military company called the Springfield Grays . He also served as quartermaster general of the Illinois militia . Civil War . During the early days of Civil War , Cook ' s militia company enlisted in Federal service in April 1861 . They formed the nucleus of Company I of the 7th Illinois Volunteer Regiment , of which Cook was appointed colonel . At the Battle of Fort Donelson , he commanded the 3rd Brigade , 2nd Division , District of Cairo , Department of the Missouri . During the Confederate breakout attempt on February 15 , Gen . Ulysses S . Grant concluded the Confederates must have weakened the opposite flank to reinforce their assault . This weakened sector lay across from the Federal brigades of Cook and Jacob G . Lauman . Lauman ' s brigade was intended as the main thrust while Cook ' s brigade would make a feint to draw away fire . Cook ' s troops nevertheless managed to capture a key Confederate artillery battery , which paved the way for the subsequent collapse of the defensive line in his sector . After the battle he was promoted to brigadier general of volunteers on March 22 , 1862 , with Senate confirmation on March 24 , 1862 , to rank from March 21 , 1862 . Cook remained in command of his brigade for a short time after Fort Donelson . Though still a colonel he was assigned to command the 6th Division in the Army of the Tennessee . This commanded was promptly turned over to Brig . Gen . Benjamin M . Prentiss who would lead the division with some notoriety at Shiloh . Cook meanwhile was transferred to brigade command in the Washington defenses . Cook later oversaw the military Department of Iowa and Dakota Territory . In the winter of 1862 – 63 , he organized a campaign against the Sioux Nation , with Sioux City , Iowa , as his base of operations . In the spring of 1863 , he was relieved by Brig . Gen . Alfred Sully . In November 1864 , he was assigned command of the military District of Illinois , replacing Eleazar Paine , who had resigned the position . Cook was mustered out of the volunteers on August 24 , 1865 . On January 13 , 1866 , President Andrew Johnson nominated Cook for appointment to the brevet grade of major general , to rank from August 24 , 1865 , and the U . S . Senate confirmed the nomination on March 12 , 1866 . Postbellum career . Following the war , Cook returned home and was elected as Sangamon County ' s representative in the Illinois General Assembly . Cook died in his home near Ransom , Michigan , in 1910 , and is interred at Oak Ridge Cemetery in Springfield , Illinois .