When Castro came to power in the mid 1950s the US was initially glad to be rid of the corrupt Batista regime. But the revolution was quickly followed by reprisals, imprisonments and deaths by firing squad. Then Castro's communist leanings became apparent as he started nationalizing private industry. Relations rapidly soured. When he allowed the Russians to secretly put missiles in Cuba, the crisis came to a head. The Soviets relented and an unsteady peace has been in force since. The US didn't help much with the ill-advised Bay of Pigs invasion.