The Old Church Slavonic sources refer to the Mojmirid rulers of Moravia consistently with the title "кнѧзь" respectively "княз" (Knez), which is also paraphrased by the Arabic word "k.náz". The Greek sources translate the Knez title consistently with "ἄρχων" (Archon), while the titulation in Latin sources is inconsistent. The dominating titles are "dux" and "rex", rarely "regulus", "princeps" and unique "comes". In what way the Knez title is referable to modern titles such as Prince, Duke or King, is matter of scholarly debate. In the pre-state period the western Slavonic tribes regularly had more than one ruler, contrary to the situation in Moravia after Mojmir I. – In: Miroslav Lysý: Titul mojmírovských panovníkov, S. 24-33; František Graus: Dux-rex Moraviae, S. 181-190; Sommer et al: Great Moravia.