Complex sentence: When Davis ordered Johnston to send Bragg to Richmond, Johnston delayed because of Mrs. Elise Bragg's illness; when her health improved Johnston was unable to assume command because of lingering medical problems from his wound at the Battle of Seven Pines in 1862.
Split into simpler sentences: When Davis ordered Johnston to send Bragg to Richmond, Johnston delayed because of Mrs. Elise Bragg's illness. When her health improved, Johnston was unable to assume command because of lingering medical problems from his wound at the Battle of Seven Pines in 1862.