According to Bartl, Kirschbaum, Štefan, and other historians, Great Moravia had two centres. According to Havlík the terms "Moravian lands" ("Moravьskskyję strany"), "Upper Moravias" ("vyšnьnii Moravě", "vyšnьneję Moravy") and "Moravian realms" ("regna Marahensium", "regna Marauorum") which were used in 9th-century documents refer to the dualistic organisation of the Moravian state, consisting of the "Realm of Rastislav" ("regnum Rastizi") and the "Realm of Svatopluk" ("regnum Zwentibaldi"). He and other historians identify the former with modern Moravia in the Czech Republic, and the latter with the Principality of Nitra in present-day Slovakia. However, this view is not universally accepted: Svatopluk's realm has also been identified with the wider region of Staré Město, or with the lands between the Danube and the Tisza or east of the Tisza.