Generate a correct and concise answer for the question based on the words in the context.
Q: Context : Frederick Charles Winkler (March 15, 1838 -- March 22, 1921) was a lieutenant colonel in the Union Army during the American Civil War who was nominated and confirmed for appointment to the grade of brevet brigadier general in 1866.
Question : Which conflict was Frederick Charles Winkler a part of?
A:
American Civil War