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.
Slovak National Council's Declaration of Independence of the Slovak Nation
The Slovak National Council's Declaration of Independence of the Slovak Nation was a resolution of the Slovak National Council on 17 July 1992, by which members of the Council demanded Slovakia's independence. This event was part of a process, which finished with the dissolution of Czechoslovakia and creation of an independent Slovakia on 1 January 1993.