On Dec. 2, 1961, Fidel Castro pronounced these prophetic words: "I am a Marxist-Leninist and will be a Marxist-Leninist until the last day of my life."
Thus, he not only confirmed what he had previously denied, but publicly unveiled an alliance with the former Soviet Union that would mark Cuba's history for 40 years, push the world to the brink of nuclear warfare, bring the island rich Russian subsidies and eventually plunge it into ruin.
On Jan. 1, 1961, the second anniversary of the Cuban Revolution, Castro had paraded Moscow military equipment through the streets of Havana.
By the end of that year, Havana's diplomatic relations with the Soviet Union had blossomed. Cuba was on its way to copying the Soviet economic and political models, with the help of $4 billion to $6 billion a year in Soviet subsidies.
Moscow sold oil to Cuba at deeply discounted prices, bought Cuban sugar at exorbitantly inflated prices and, on top of everything, sent tons of communist "internationalist" aid.
Concerned about Cuba's place in the socialist world and fearful that the United States would try again to invade Cuba, Castro agreed to let Moscow install nuclear missiles on the island in the fall of 1962.
The United States' discovery of the missiles during a spy overflight set off the October missile crisis, until Soviet Premier Nikita Khrushchev agreed to withdraw the missiles, pulling back from the brink of nuclear war on Oct. 28, 1962.
Castro fumed that Khrushchev did not consult him on the agreement, but he nevertheless continued to move closer ideologically to Moscow. In 1976, Havana adopted a new constitution, based on the Soviet Constitution of 1936. It described Cuba as a socialist state and gave power exclusively to the Communist Party.
The Soviet and Cuban economies became intimately linked: The island relied on the Soviet trading bloc known as COMECON for nearly 85 percent of its trade. The Soviet Union was its main source for oil, grain, flour, canned meat and other processed foods, automobiles and trucks, tires, spare parts and industrial machinery, as well as basic items like detergents, razor blades and toothpaste.
The relationship began to deteriorate in the late 1980s, amid Soviet Premier Mikhael Gorbachev's pursuit of political and economic reforms that the Cuban leadership viewed with dismay.
While the reforms were applauded in most of the world, they caused economic disruptions in the Soviet Union that were reflected in Cuba deliveries of Soviet goods to the island fell far behind schedule, if they arrived at all.
When the Soviet Union ceased to exist in 1991, Moscow halted its massive subsidies to Havana. Castro was left to cultivate new, more capitalist relations with Russia and the other former socialist republics.
Havana, meanwhile, refused to repay its estimated $21 billion debt to the Soviet Union, insisting that the money was owed to "a country that no longer exists."
It was not until 2001 that Russia drove the final spike into its relations with its former Cold War ally by closing its massive electronic eavesdropping facility at Lourdes, near Havana, and halting the estimated $200 million in rent that Moscow had been paying annually to Cuba for the facility.
"They were our allies against the capitalist empire, our best friends, our tovariches," said one former Havana university professor. "Now they are gone, nobodies."