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.
Andrej Hlinka
At the end of World War I, Hlinka significantly contributed to the creation of Czechoslovakia. On the confidential meeting of the Slovak National Party on 24 May 1918, he took a clear position and ended a prolonged discussion of undecided participants (""Thousand years old marriage with the Hungarians goes wrong. We have to divorce."") He became a member of the Slovak National Council and signed the Martin Declaration, which advocated a political union with the Czech nation. In the early period of Czechoslovakia, when a part of the Church hierarchy still preferred the Kingdom of Hungary, he intensively lobbied for the new state.