Czech Republic

After the period of migration of peoples (barbarian invasions), the Czech lands were settled by Slavic tribes.

An excerpt from the article 27 facts about Czech Republic

The first known state in Czech lands was established in 623, when Samo (a Frankish merchant who united several Slavic tribes) and was elected "Slavic king" (Rex Sclavorum), successfully defended his kingdom against the Franks in the three-day Battle of Wogastisburg.

The next state that appeared on Czech lands after the dissolution of the Samo state was probably Great Moravia. The center was located in Moravia and today's western Slovakia. In 863, Cyril and Methodius, two Greek scholars, brought Christianity to Great Moravia and established the first Slavic writing system, the Glagolitic script. Great Moravia fell during the Magyar invasion in the early 10th century.