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.
Jozef Tiso's speech in Holič
In March 1939, the Slovak State declared independence from Czechoslovakia; Germany invaded the Czech rump state. That October, Jozef Tiso, a Catholic priest, became president of Slovakia. Slovakia was the only country to pay for the deportation of its Jewish population, and the only country besides Nazi Germany to organize the deportation of its own Jewish citizens. In an 8 March petition, Slovak Jewish community leaders exhorted Tiso to cancel the planned deportation of Slovakia's Jews because it represented the "physical destruction of the Jews in Slovakia". Tiso ignored the petition, as well as the condemnation of papal ambassador Giuseppe Burzio. At the time of Tiso's speech, 55,000 Jews out of 89,000 had been deported from the Slovak State; the deportations had been halted on 1 August 1942. The Slovak government knew that the deportees were being systematically murdered.