Definition: Generate a correct and concise answer for the question based on the words in the context.
Input: Context : William Cogswell (August 23, 1838 -- May 22, 1895) was a U.S. Representative from Massachusetts and a colonel in the Union Army during the American Civil War who was awarded the honorary grade of brevet brigadier general, U.S. Volunteers.
Question : Which historic war did William Cogswell participate?
Output:
American Civil War