This Day in American Military History

10 August

1861: The second major land engagement of the Civil War—Wilson’s Creek, Missouri. Union general Nathaniel Lyon was killed on Bloody Ridge as his troops repulsed rebel charges. After his death, Union troops pulled back to Rolla, Missouri, giving the Confederates their second major victory in the young war.

1949: President Truman signed an amendment to the National Security Act (September 18), which changed the War Department to the present-day Department of Defense.

Brandus, Paul. This Day in U.S. Military History (p. 196). Bernan Press. Kindle Edition.