Initially, he had only criticised Stalin, which was not new as Khrushchev had done so in 1957.
Tsypko went further and publicly criticised Marx and Lenin, attacking the foundations of Communism.
From 1988, citizens were allowed to listen to foreign radio and newspapers.
The Nineteenth Party Congress of June 1988 admitted the scale of problems facing the USSR, including inadequacies in health and education and poverty in rural areas.
This was a huge contrast to traditional high profile meetings which claimed the Communist Party was consistently successful in improving the lives of all.
The scale of the weaknesses shook the public faith in the Communist Party.