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.
Slovakia
The Slavs arrived in the territory of present-day Slovakia in the 5th and 6th centuries. In the 7th century, they played a significant role in the creation of Samo's Empire and in the 9th century established the Principality of Nitra, which was later conquered by the Principality of Moravia to establish Great Moravia. In the 10th century, after the dissolution of Great Moravia, the territory was integrated into the Principality of Hungary, which would become the Kingdom of Hungary in 1000. In 1241 and 1242, much of the territory was destroyed by the Mongols during their invasion of Central and Eastern Europe. The area was recovered largely thanks to Béla IV of Hungary who also settled Germans which became an important ethnic group in the area, especially in what are today parts of central and eastern Slovakia. After World War I and the dissolution of the Austro-Hungarian Empire, the Czechoslovak National Council established Czechoslovakia (1918–1939). A separate (First) Slovak Republic (1939–1945) existed during World War II as a totalitarian, clero-fascist one-party client state of Nazi Germany. At the end of World War II, Czechoslovakia was re-established as an independent country. A coup in 1948 ushered in a totalitarian one-party state under the Communist regime during whose rule the country existed as a satellite of the Soviet Union. Attempts for liberalization of communism in Czechoslovakia culminated in the Prague Spring, which was crushed by the Warsaw Pact invasion of Czechoslovakia in August 1968. In 1989, the Velvet Revolution ended the Communist rule in Czechoslovakia peacefully. Slovakia became an independent state on 1 January 1993 after the peaceful dissolution of Czechoslovakia, sometimes known as the Velvet Divorce.