Complex sentence: Although refusing to categorize his regime as socialist and repeatedly denying being a communist, Castro appointed Marxists to senior government and military positions; most notably, Che Guevara became Governor of the Central Bank and then Minister of Industries.
Split into simpler sentences: Although refusing to categorize his regime as socialist and repeatedly denying being a communist, Castro appointed Marxists to senior government and military positions. Most notably, Che Guevara became Governor of the Central Bank and then Minister of Industries.