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.
Protectorate of Bohemia and Moravia
On 10 October 1938, when Czechoslovakia was forced to accept the terms of the Munich Agreement, Germany incorporated the Sudetenland, on the Czechoslovak border with Germany and Austria proper, with its majority of ethnic German inhabitants, directly into the Reich. Five months later, when the Slovak Diet declared the independence of Slovakia, Hitler summoned Czechoslovak President Emil Hácha to Berlin and intimidated him into accepting the German occupation of the Czech rump state and its reorganisation as a German protectorate.