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.
Tanks of Czechoslovakia
Thereafter, Czechoslovakia came under continuous pressure from the revisionist governments of Germany and Hungary. Eventually, this led to the Munich Agreement of September 1938, which allowed Nazi Germany to partially dismember the country by occupying what was called the Sudetenland, a region with a German-speaking majority bordering Germany and Austria. The Germans seized a large amount of the Czechoslovakian designed tanks and armored vehicles when they occupied Bohemia-Moravia in March 1939. The remainder of "rump" Czechoslovakia was renamed Czecho-Slovakia and included a greater degree of Slovak political autonomy.
After the Munich Agreement and its Vienna Award, Nazi Germany threatened to annex part of Slovakia and allow the remaining regions to be partitioned by Hungary or Poland unless independence was declared. Thus, Slovakia seceded from Czecho-Slovakia in March 1939 and allied itself, as demanded by Germany, with Hitler's coalition. The government of the First Slovak Republic, led by Jozef Tiso and Vojtech Tuka, was strongly influenced by Germany and gradually became a puppet regime in many respects.