Before Fidel Castro took over the island state's government; Cuba was under the military rule of President Fulgeneio Batista. Castro was the leader of the 26 July Army, a rebel movement, which launched a resistance campaign against Batista's government. A battle ensued between the rebel guerrillas and the Cuban army in the town of Santa Clara, the capital of the province of Las Villas. Although outnumbered by the government forces the rebels enjoyed popular support and managed to register some victories. On New Year's Day 1959 the 26 July Army finally forced Batista into exile, and Castro turned Cuba into the only communist state in the Western Hemisphere. On 7 May 1960 Castro re-established formal diplomatic ties with the Soviet Union, which had been cut during the Batista rule.
References

Sierra, J.A., Batista, from History of Cuba, [online], Available at www.historyofcuba.com [Accessed: 29 February 2014]|BBC, Cuba Profile, from BBC, [online],  Available at news.bbc.co.uk [Accessed: 29 January 2014]