Great Moravia was first state formation that with its area had reached also the area of present Slovakia. It had been formed by merging of independent Moravian and Nitrian principalities in the 9th century. Its inhabitants were ascendants of Slovaks and Czechs. Character of the Great Moravian State we can mark as relatively centralized formation, where ruler and his family has dominated status. Despite the time of its creation this formation showed all most important signs of state. It has relatively well developed system of state bodies, system of local bodies as example of structured state area into smaller local units. Existing legal system in this area had ultimate signs of customary law, in the same time usage of written legal documents existed. During its existence Great Moravia had also independent church organization and it performed independent foreign policy. During its existence this state has been recognized as independent unit also from Pope. The most critical fact that contributed to downfall of Great Moravia in 10th century were on one side conquests of Hungarian tribes as well as conflicts in the rulers family. The existence of Great Moravia is in Slovakia for centuries accepted as important milestone of Slovakian nation in its attempts for achieving Slovakian state independency.