The legend of the three brothers Lech, Cech, and Rus, who became the ancestors of the Polish, Czech, and Rus, explains how these cultures were created. The legend involves the brothers being the son of prince Pan and leaving the Pannonia empire. Some accounts don’t involve Rus, rather just Lech and Cech, who are the sons of Jan and not Pan.
Great Moravia: Svatopluk I and Mojmir II (870-907)
The story of Great Moravia continues with the arrest of Svatopluk I's arrest. Becuase of Svatopluk's supposed death, the Moravians, in anger, elected Slavomir in his place until Svatopluk came back. After the death of Svatopluk II, his son Mojmir II took his place, after which the kingdom saw some hard times, including wars.