In April 1949 the USA , Britain, France and 9 other Western countries formed NATO. This was a military alliance intended to protect Western countries from the communist threat. All members agreed that if one was attacked, the others would come to its aid. In response to the FRG joining NATO in May 1955, Stalin created the Warsaw Pact, the equivalent of NATO for eastern communist countries. This was now seen as a defining moment in the split of Europe into two blocs: the capitalist West and the communist East.