Peter Valentine Hagner (August 28, 1815 – March 11, 1893) was an officer of ordnance who served for over 40 years in the United States Army and was Brevetted Brigadier General.
Early life
Hagner was the son of government auditor Peter Hagner, and was born in Washington, D.C. After graduating the United States Military Academy at West Point, New York, Hagner was assigned first to artillery, then topographical engineers, and finally ordnance in 1838, in which department service he spent the balance of his career.
Career
At the outset of the Mexican–American War, First Lieutenant Hagner was assigned to the siege battery company, and was brevetted captain and major for "gallant and meritorious conduct" in battles leading to the capture of Mexico City in 1847. In the years before the American Civil War, Hagner commanded several arsenals, responsible for maintenance and upkeep on weaponry and military stores.
Considered a moderate unionist with a reputation of being a level-headed career soldier, the James Buchanan administration selected Hagner to command of the strategic St. Louis Arsenal at the outbreak of the war. The arsenal at the time was sought by both Union and Confederate sympathizers for its valuable contents, and during the early days of the war both legitimate and partisan guerrilla military units from both sides schemed to obtain control.
