Declassified documents released by the U.S. National Security Archive on Friday indicate that the earliest known attempt by the Central Intelligence Agency (CIA) to assassinate a leader of the Cuban revolution dates back to 1960. An agent offered a pilot $10,000 to "arrange an accident" on Raul Castro's return journey from Prague to Havana. The documents reveal that the pilot, named Jose Raul Martinez, recruited by the CIA, requested that the United States fund his sons' university education in the event of his death during the operation. The CIA agreed to this, according to documents from the Washington-based National Security Archive Research Institute. However, after Martinez took off for Prague, the CIA office in Havana received an order to cancel the mission without being able to contact the pilot. Upon his return, the pilot indicated that he "was unable to arrange the accident that was sought." This information comes as Raul Castro, 89 years old and brother of Fidel Castro, prepares to withdraw from Cuban political life by stepping down as the leader of the Cuban Communist Party. Following Fidel Castro's death in 2016, Raul Castro's departure marks the end of an era in Cuba's history, which has been defined solely by the leadership of the two brothers.