In February the Organization of Afro-Asian Solidarity held a conference in Algiers - for 63 African and Asian countries as well as 19 national liberation movements.
Che spoke about his theory of moral rather than financial incentives, and raising it to an international level. He criticised the Soviet Union and every socialist country which - in his view - continued to exploit people. He called for a new bond between all socialist peoples to foster cooperation and coordination and lead to genuinely socialist relations among them, to the benefit of all. [His full speech]
On 24th February 1965 Che's last child, Ernesto (Ernestito) was born. Aleida had a procedure so she could have no more children.

From Algiers, Che went to the United Arab Republic where he stayed between 3rd and 12th March. He visited the main industrial plants, talked to Egyptian workers and of course President Nasser - in whose company Che said: "The turning point in each man's life is the moment in which he decides to face death. If he faces death then he is a hero whether he becomes a success or not." And on the last day of his visit he said that he hoped to find "a place to fight for world revolution and to accept the challenge of death."

On 14th March Che arrived back at Havana and completely disappeared from the public.
Three months earlier a group of 150 men had begun training in guerrilla warfare - all of them were black - except their leaders, Che and José María Martínez-Tamayo, his head of intelligence. As Cuba didn't want to be accused of foreign interference in an internal African matter, they were called military instructors. Their destination was the Congo.
The area of Luluabourg (on the western shore of Lake Tanganyika) had been liberated by Congolese rebels. Che believed that the creation of a foco, led by the Cubans, would attract guerrillas from the surrounding areas and the neighbouring countries and this would contribute to the liberation of the Congo. After the success of the plan, the Cubans would have gone back home while the Congolese would have governed their own country.
Che studied the Congo, its background, history and culture, still factors like tribal divisions and a huge belief in black magic devastated Che's hopes and expectations.

On 1st April Che gave his farewell letter to Fidel Castro. In that letter he formally resigned his post as minister, his rank of commandante and his Cuban citizenship. Nothing legal bound him to Cuba anymore. [Che's letter]
He also sent a letter to his parents. His mother could never read it because by the time it arrived at Buenos Aires, she had died of breast cancer. In their last letter Che had told her that he had been about to break away from his ministerial commitments, spend a month in Oriente cutting cane, then spend five years running an industrial complex. His mother had suspected that he had had other plans - while hiding the fact from her son that she had been dying.
He also wrote to his children to grow up as good revolutionaries and study hard. He left Aleida a tape recording of some poems of Pablo Neruda (his favourite poet) and he promised to send for her when the situation had become stable.
He met his younger children in disguise before he left - but he couldn't meet Hildita because she would have recognised him.
On 19th April he left in disguise (he had shaven his moustache and his beard, and he wore glasses) for Tanzania with Victor Dreke and José María Martínez-Tamayo. His men arrived from Cuba in small groups.
On 20th April Fidel Castro told to the foreign press: "All I can tell you is that Comandante Guevara is always wherever he can be most useful to the revolution, and that relations between him and myself are excellent." Rumours were spreading that Che died, being murdered by Fidel Castro because of their differences, that he was admitted into a lunatic asylum and that he disappeared because of his economical failures.
On 24th April Che and his thirteen Cuban men left Tanzania for the Congo. Che hid his identity and observed the camp and the Congolese soldiers. He was horrified to see that there was no discipline and there was too many divisions among people. There were also language problems: some people didn't speak French - or not even Swahili.
The leaders spent their time on drinking and sex, away from the camp - instead of training their soldiers and fighting.

On 18th May 1965 Celia de la Serna died in a clinic in Buenos Aires.
Che learnt the news of her mother's being very ill on 22nd May and he was devastated. He got to know about her death only a month later though he had suspected of it since he was told that she had been dying. He wrote a moving short story about it: [Che Guevara: La Piedra]

In the Congolese camp Che listened to the radio in the morning - mostly in French, but sometimes in English even if he had never completely mastered the language. He studied Swahili and taught French, Spanish and mathematics from 2 to 4 in the afternoon. He walked 2-3 kilometres a day, then soon the physical training started too. He also practised medicine when someone needed treatment. He was often tortured by asthma and malaria.
He wrote to Aleida to be strong, to love him passionately, to educate their children and to prepare for the time when she could join him in the Congo as a combatant. He also asked her to send him a couple of books like the complete works of Shakespeare, ancient Greek plays and philosophical works and a book of geometry exercises. (He thought that the campaign would last for at least ten years.)

Things didn't go well. It was very difficult to teach discipline to the Congolese soldiers - or to teach them shoot well and stay in position after the enemy appeared and not to leave their arms behind. The black magic, the ill-treatment of the prisoners and the cannibalism, practiced by some of these soldiers also caused problems.
On 19th June Che's friend, the Algerian president, Ben Bella was overthrown and the Congolese campaign lost a huge supporter.
In August Che wrote that it would be impossible to win a war when the local leaders were always absent - it also annoyed him during the campaign, besides the lack of discipline, organisation and sacrifice. The Congolese didn't seem to want to fight for their own independence.

On 3rd October Fidel Castro read Che's farewell letter in public. Che heard it on the radio and he was unhappy about it - the fact that he had given up his Cuban nationality alienated him from his men.
On 23rd October the Congo's president Kasavubu announced that the white mercenaries would leave the country and the rebellion was considered to be over. This meant that the African states withdrew their support from the campaign.

By 20th November Che and his men left the Congo for Tanzania. The Congolese campaign was over - and failed.  
Che was very disappointed and he saw his own faults as well. In the camp he wore the name Tatu (meaning 'three' in Swahili), as if he were the third commander. [Victor Dreke was 'Moja' (meaning 'one') and José María Martínez-Tamayo was Mbili (meaning 'two'). It confused the Congolese to see that however Moja should be the leader, still it was Tatu who always gave the orders and with whom every problem was consulted. Che learnt that he should have led the campaign from the start.

Between December 1965 and January 1966 Che stayed in Tanzania, in the grounds of the Cuban embassy, writing the account of his experience (the Congo Diary that was published later), while the Cuban combatants returned home.
Fidel Castro sent Aleida to Tanzania so she and Che could spend a little time together - without their children or friends or bodyguards who were always present in their Havana home. It was like a honeymoon for them - that they didn't have after their wedding.