At around 11pm on the 20th August 1968, troops from the USSR, Bulgaria, Poland and Hungary entered Czechoslovakia in an invasion that brought the Prague Spring to an end. The invasion, known as Operation Danube, led to almost half a million soldiers crossing the border to bring Alexander Dubček’s reforms to an end.

The Prague Spring began in early January, shortly after Dubček became the leader of Czechoslovakia. Keen to push forward with de-Stalinisation within the country, he granted greater freedom to the press and introduced a programme of ‘socialism with a human face’ by which he intended to decentralise parts the economy and introduce some limited democratic reforms.

This new openness saw open criticisms of the Czechoslovakian government begin to appear in the press, which concerned the other Warsaw Pact countries. János Kádár, the leader of Hungary who came to power after the fall of Imre Nagy in 1956, even warned that the situation in Czechoslovakia seemed “similar to the prologue of the Hungarian counterrevolution”.

Concerned that Dubček’s reforms might spread to other Eastern Bloc countries and threaten the USSR’s security, the Soviet leader Brezhnev chose to open negotiations with the Czechoslovakian leadership that lasted into August. The talks ended in compromise, but Brezhnev continued to be unhappy with the situation and began to prepare military intervention.

Overwhelmed by the military invasion, Dubček asked his people not to resist. 72 Czech and Slovak soldiers and 108 civilians were killed, with a further 500 civilians injured. It later emerged that members of the Czechoslovakian government had asked for Soviet assistance against Dubček’s reforms.

On the 5th January 1968, the Prague Spring began when Alexander Dubček became the new First Secretary of the Communist Party of Czechoslovakia. The Prague Spring lasted for just over seven months before the Soviet Union, along with other members of the Warsaw Pact, invaded Czechoslovakia to bring the reforms to a halt.

Dubček was a committed Communist, and had been First Secretary of the regional Communist Party of Slovakia since 1963. However he struggled to work with Antonín Novotný, the President of Czechoslovakia, under whose control the country experienced a slow and uneasy move towards destalinization while suffering a huge economic downturn. Frustrated by Novotný’s failure to effectively restructure the country, Dubček and other reformists challenged him at a meeting of the Central Committee in October 1967. In response Novotný secretly invited the Soviet leader Leonid Brezhnev to visit Czechoslovakia to secure his support. However, this plan backfired when Brezhnev learned just how unpopular Novotný was and instead lent his support to remove him from power.

Consequently Dubček replaced Novotný as First Secretary on the 5th January 1968, and quickly began to introduce a series of political reforms. Known as “socialism with a human face” this political programme was intended to maintain Communist control of the government while allowing mild democratisation and political liberalisation. However, as the reforms took hold the government was faced with public demands to go even further. At the same time, the USSR and other Warsaw Pact countries began pressuring Dubček to bring the Prague Spring under control. On the 20th August they took matters in to their own hands and invaded Czechoslovakia.

On the 29th September 1938, Adolf Hitler, Neville Chamberlain, Benito Mussolini and Édouard Daladier reached an agreement on the Nazi annexation of the Sudetenland areas of Czechoslovakia. Seen by many as the ultimate act of failed appeasement, the Munich Agreement that was tabled on the 29th and signed in the early hours of the 30th was broken by Hitler six months later when he annexed the rest of Czechoslovakia.

As a result of the Treaty of Versailles at the end of the First World War, Germany had lost territory to the newly-created state of Czechoslovakia. Following his rise to power in Germany, Hitler set about reuniting with ethnic Germans. After the Czechoslovakian government turned down the Sudetenland’s branch of the Nazi Party request for autonomy from the rest of Czechoslovakia, which had been encouraged by Hitler, tensions between the two countries rose.

By the autumn of 1938 the situation had become a crisis, and Britain’s Prime Minister Neville Chamberlain had begun to engage Hitler in discussions aimed to avoid war. Britain and France were both desperate to reach a peaceful resolution and, when faced with Hitler’s demand to annex the Sudetenland but make no further territorial demands in Europe, the leaders eventually agreed.

Czechoslovakia had no option but to agree to the terms of the agreement, despite not being involved in the discussions. Meanwhile Chamberlain returned to Britain and made his famous speech in which he referred to the Munich Agreement and the related Anglo-German Declaration as securing “peace for our time”. Sadly he was wrong. Britain declared war on Germany less than a year later.