Hardly installed in power, the revolutionary government began to dismantle the neocolonial political system. The repressive bodies were dissolved and citizens were guaranteed, for the first time in long years, the full exercise of their rights. The public administration was cleaned up and misappropriated assets were confiscated.  In this way that fatal practice of republican life was eradicated. Batista war criminals were tried and punished, the corrupt leadership of the labor movement was swept away, and the political parties that had served the tyranny were dissolved. Fidel Castro is appointed Prime Minister in February 1959. 
According to topschoolsintheusa, the United States government had made no secret of its displeasure at the Triumph of the Cuban Revolution and, after promoting a malicious press campaign, adopted a policy of systematic harassment against Cuba, encouraging and supporting counterrevolutionary movements with the purpose of destabilizing the country. The obstacles imposed by President Manuel Urrutia to the revolutionary transformations in July led to the resignation of Fidel Castro from the premiership, a position to which he would return days later amid massive demonstrations of support that led to the resignation of the president and his replacement by Osvaldo Dorticós. In October a military sedition aborted in Camagüey orchestrated by the head of that plaza, Commander Hubert Matos, in open collusion with landowners and other counterrevolutionary elements in the town.  Meanwhile, increasing acts of sabotage and terrorism began to claim innocent victims.
In July 1960, after learning of the abolition of the Cuban sugar quota by the Washington government, Fidel Castro announced the nationalization of all North American properties on the island.  This measure would be followed, a few months later, by the decision to nationalize the companies of the Cuban bourgeoisie that, definitively aligned with the United States and the oligarchic sectors, had indulged in systematic undercapitalization and economic sabotage maneuvers. But the North American aggressions were not limited to the field of the economy. While it promoted the creation of counterrevolutionary organizations and bands of insurgents in different regions of the country, to which it supplied arms and other supplies, the Dwight Eisenhower administration –Which broke relations with Cuba in January 1961– had begun the preparation of a mercenary brigade with the purpose of invading the island.
The invasion would begin on April 17 in the Playa Girón area, after a surprise bombardment of Cuban air bases. At the burial of the victims of this attack, Fidel Castro proclaimed the socialist character of the Revolution, something that was already perceived from the measures taken in the final months of 1960. 
It took less than 72 hours for the people to crush the mercenary brigade that the Central Intelligence Agency (CIA) had taken months to train. Despite this historic defeat, the United States did not give up its intention of crushing the Cuban Revolution.
The 3 of February of 1962 by Presidential Executive Order 3447 total “embargo” on trade between the United States and Cuba was formally implemented. What in reality is a blockade that continues to this day, has cost the Cuban economy numerous losses, and has even claimed human lives.
Between October 22 and 28, 1962, one of the most dramatic events of the Cold War and in the opinion of some specialists, of all contemporary international relations, involved the governments of Cuba, the United States and the Soviet Union: The Crisis October, generated as a result of the discovery by the United States of Soviet nuclear missile bases in Cuban territory.
Banditry, another action encouraged and financed by the United States government, was definitively liquidated in 1965, when the last organized gang to perform in the country, that of Juan Alberto Martínez Andrades, was captured on July 4. Other scattered bandits who tried to flee from the revolutionary justice were captured during the following months.
In the international arena, the United States managed to separate Cuba from the Organization of American States (OAS) and most of the Latin American nations, except for the honorable exception of Mexico, broke relations with Cuba. However, the Cuban Revolution strengthened its ties with the socialist camp and the Third World countries, participated in the constitution of the Movement of Non-Aligned Countries and developed an active policy of solidarity towards national liberation movements and support for the same. The nation that resolutely resists all kinds of armed aggression should also survive the tight economic siege.
In the midst of notable economic difficulties, it was possible to eliminate unemployment and guarantee the population the satisfaction of their fundamental needs. A vast literacy campaign in 1961 removed the old scourge of illiteracy.
Immersed in the development and improvement of this work was the Revolution when the collapse of the socialist camp and the disintegration of the Soviet Union took place. These events were dramatically reflected in Cuban society, since the country’s economy was integrated into that community. In 1989, Cuba concentrated 85 percent of its commercial relations with the USSR and the rest of the socialist camp.
In 1991, the IV Congress of the PCC was held in which the situation was analyzed and the need to save the Homeland, the Revolution and Socialism was specified.  In this congress, important agreements were made regarding the modifications to the Constitution, the Party statutes, and the foundations of the strategy to resist and begin the recovery were laid. In the strategy outlined, a series of measures were put into practice aimed at achieving increased economic efficiency and competitiveness, internal financial consolidation, solutions to internal indebtedness; reintegration into the international economy, encourage the investment of foreign capital, the strengthening of the Cuban state enterprise, a necessary condition and without which there can be no socialism.