Complex sentence: Smith was wounded at First Bull Run and distinguished himself during the Heartland Offensive, the Confederacy's unsuccessful attempt to capture Kentucky in 1862, before being made commander of the Trans-Mississippi Department in January 1863.
Split into simpler sentences: Smith was wounded at First Bull Run and distinguished himself during the Heartland Offensive, the Confederacy's unsuccessful attempt to capture Kentucky in 1862. He was appointed as commander of the Trans-Mississippi Department in January 1863.