King of the Slavs

King of the Slavs ({{langx|la|rex Sclavorum, Sclavorum rex}}) was a title denoting some Slavic rulers, as well as Germanic rulers that conquered Slavs, in the Middle Ages in European sources, such as Papal correspondence.

Papal use is bolded.

;Slavic

• Samo, ruler of Samo's Empire and the "Slavs" (623–658); in the Frankish Annals
• Drogoviz, ruler of the Veleti (789); in Annales Mettenses priores in {{circa}} 805{{cite book|author=Adalbert-Stifter-Verein (Munich, Germany)|title=Veröffentlichungen der Wissenschaftlichen Abteilung|url=https://books.google.com/books?id=-O8fAAAAMAAJ|year=1961|publisher=Edmund Gans Verlag|page=26}}
• Trpimir I, ruler of Duchy of Croatia (845–864); erroneously by Gottschalk in the 840s{{cite book|author=John V. A. Fine|title=When Ethnicity Did Not Matter in the Balkans: A Study of Identity in Pre-Nationalist Croatia, Dalmatia, and Slavonia in the Medieval and Early-Modern Periods|url=https://books.google.com/books?id=wEF5oN5erE0C&pg=PA36|date=5 February 2010|publisher=University of Michigan Press|isbn=978-0-472-02560-2|pages=36–}}
• Svatopluk I of Moravia, ruler of Great Moravia (870–894); by Pope Stephen V in 885{{cite book|author=Maddalena Betti|title=The Making of Christian Moravia (858-882): Papal Power and Political Reality|url=https://books.google.com/books?id=MdLYAQAAQBAJ&pg=PA189|date=24 October 2013|publisher=BRILL|isbn=978-90-04-26008-5|pages=189–}}
• Michael, ruler of Zachlumia (913–926); erroneously in the Annales Barenses{{cite book|author=Armin Pavić|title=Postanje Gundulićeva Osmana i glávâ 29-36 u Porfirogenitovoj De adm. imp|url=https://books.google.com/books?id=wHtEAQAAMAAJ|year=1906|publisher=Tisak Kr. zemaljske tiskare|page=62}}
• Mihailo Vojislavljević, ruler of Duklja (1050–1081); by Pope Gregory VII in 1077{{sfn|Ćirković|2004|p=26}}
• Constantine Bodin (Bodin Vojislavljević), ruler of Duklja (1081–1101); by the chronicle of Orderic Vitalis, relating to events of 1096{{sfn|Jireček|1911|p=241}}
• Stefan Dragutin, ruler of Kingdom of Serbia (1276–1282) and Syrmia (Realm of Stefan Dragutin; 1282–1316); by Pope Nicholas IV in 1288{{cite book|title=Concise Dictionary of Proper Names and Notable Matters in the Works of Dante|year = 1968|url=https://books.google.com/books?id=jfVFeveiJLIC&pg=PA566|publisher=Ardent Media|pages=566–|id=GGKEY:P53U8KC8WZR|quote=

Addressed (in 1288) by Pope Nicholas IV as 'Rex Sclavorum'; he signed himself (in 1305 or 1307) in a document still extant in the Venetian archives as ' Stephanus Urosch Rex Serbicarum terrarum et maritimarum '. a [Stefano Urosio.] ...}}

;Non-Slavic

• Canute Lavard, Danish prince (1120–1131); by Abbott Wilhelm after 1129{{cite book|author=Christian Raffensperger|title=Reimagining Europe: Kievan Rus' in the Medieval World|url=https://books.google.com/books?id=1BXlXAkBKs0C&pg=PA103|date=12 March 2012|publisher=Harvard University Press|isbn=978-0-674-06546-8|pages=103–}}
• Canute VI, King of Denmark; by himself in 1185, after a conquest of Pomerania{{cite news | url=https://www.britannica.com/biography/Canute-VI | title=Canute VI | Viking ruler, Danish monarch | Britannica | newspaper=Encyclopedia Britannica | date=20 February 2024 }}