Theodore Runyon was an American politician, diplomat, and American Civil War brigadier general in the New Jersey Militia, serving with the Union Army at the Battle of First Bull Run. Runyon was a lawyer before the Civil War and mayor of Newark, New Jersey, a major general in command of the New Jersey National Guard until 1873, first president of the Manufacturers' National Bank of Newark, chancellor of New Jersey for 14 years and, between 1893 and 1896, envoy and later ambassador to Germany.

The First Battle of Bull Run, called the Battle of First Manassas by Confederate forces, was the first major battle of the American Civil War. The battle was fought on July 21, 1861, in Prince William County, Virginia, just north of what is now the city of Manassas and about thirty miles west-southwest of Washington, D.C. The Union Army was slow in positioning themselves, allowing Confederate reinforcements time to arrive by rail. Each side had about 18,000 poorly trained and poorly led troops. The battle was a Confederate victory and was followed by a disorganized post-battle retreat of the Union forces.