Complex sentence: Robert E. Lee wore this insignia due to his former rank in the United States Army and refused to wear the insignia of a Confederate general, stating that he would only accept permanent promotion when the South had achieved independence.
Split into simpler sentences: Robert E. Lee wore this insignia in respect to his former rank in the United States Army. Lee refused to wear the insignia of a Confederate general, stating that he would only accept permanent promotion when the South had achieved independence.