Henry Wager Halleck

Henry Wager Halleck (January 16, 1815 – January 9, 1872) was a United States Army officer, scholar, and lawyer. A noted expert in military studies, he was known by a nickname that became derogatory: "Old Brains". He was an important participant in the admission of California as a state and became a successful lawyer and land developer. Halleck served as General-in-Chief of all Union armies from 1862 to 1864 during the American Civil War.
https://en.wikipedia.org/wiki/Henry_Halleck