Czech Republic–Slovakia relations
Before 1918, both countries were part of Austria–Hungary. However, after the Ausgleich of 1867 Czechia belonged to the Austrian Empire while Slovakia belonged to the administratively separate Kingdom of Hungary, and between 1918 and December 31, 1992, both countries were part of Czechoslovakia. 
Both countries established diplomatic relations on January 1, 1993. These international relations are usually referred to or described as "very good", "cordial", and "above standard" in the media. When a Czech or Slovak president is inaugurated, very often his first international visit is to the former part of the common country. The same custom applies to newly elected prime ministers of the Czech Republic and Slovakia.
First Czechoslovak Republic
After 1933, Czechoslovakia remained the only functioning democracy in Central Europe. Under pressure from its Sudeten German minority, supported by neighbouring Nazi Germany, Czechoslovakia was forced to cede its Sudetenland region to Germany on 1 October 1938 as part of the Munich Agreement. It also ceded southern parts of Slovakia and Subcarpathian Ruthenia to Hungary and the Zaolzie region in Silesia to Poland. This, in effect, ended the First Czechoslovak Republic. It was replaced by the Second Czechoslovak Republic, which lasted less than half a year before Germany occupied the rest of Czechoslovakia in March 1939.