Felix Kirk Zollicoffer
This Tennessee-born newspaper editor and Whig politician fought in the Seminole War as a first lieutenant, held various offices in Tennessee and served in the U.S. House of Representatives (1853-59). Although a staunch supporter of states' rights, he worked to avoid a confrontation between North and South and attended the 1861 peace conference in Washington.
Felix Zollicoffer was made a brigadier general in the Tennessee state forces following the fall of Fort Sumter, transferred into Confederate service, with the same rank, on July 9, 1861, and given command of the District of East Tennessee, Department Number 2, on August 1, with the assignment to "preserve peace, protect the railroad, and repel invasion." This was a difficult task since eastern Tennessee was generally not a slaveholding area and was unsympathetic to the Confederate cause.
Zollicoffer moved his forces into southeastern Kentucky in late 1861 before being superseded by General G.B. Crittenden on December 8. Zollicoffer was then given command of the Ist Brigade of the district. His rash move across the Cumberland River forced the rebels to give battle, at a disadvantage, at Mill Springs on January 18, 1862.
While studying the field he came across another officer on the same mission. He told that officer not to fire on his own men. But the other man was Colonel Speed S. Fry of the 4th Kentucky, a Union regiment. After riding away and being fired upon, Fry, realizing his mistake, turned and shot the Confederate. Also fired upon by some other Federals, Zollicoffer fell dead. (Myers, Raymond E., The Zollie Tree)
Source: "Who Was Who In The Civil War" by Stewart Sifakis
Zollie's Folly Just a little explanation of what it was that got the General killed.