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.
Second Czechoslovak Republic
The Second Czechoslovak Republic (, ), sometimes also called the Czech-Slovak Republic (Czech and ), existed for 169 days, between 30 September 1938 and 15 March 1939. It was composed of Bohemia, Moravia, Silesia and the autonomous regions of Slovakia and Subcarpathian Ruthenia, the latter renamed as of 22 November 1938 as Carpathian Ukraine ("Karpatská Ukrajina" in Czech).