Complex sentence: He was rival of Fidel Castro in the bloody feuds of the trigger happy Action groups and subject of at least one failed attempt by Castro to kill him; however, he also participated with Castro in the Cayo Confites plot to overthrow Dominican Republic Dictator Rafael Trujillo.
Split into simpler sentences: He was rival of Fidel Castro in the bloody feuds of the trigger happy Action groups and subject of at least one failed attempt by Castro to kill him. Masferrer also participated, with Castro, in the Cayo Confites plot to overthrow Dominican Republic Dictator Rafael Trujillo.