Kingdom of Ailech - Cóiced Ailech (Old Irish ones are subject to change if I can find a better source)
Duchy of Alemannia - Ducatus Alemanniae (Most "duchies" are in Latin, as they're part of the Frankish kingdom generally)
Alt Clut - Ystrad Clud
Angria - Angrarii (I think this one is also Latin, but I can't find the Old High German for it)
Duchy of Aquitaine - Ducatus Aquitaniae
Kingdom of Asturias - Regnum Asturorum
Avars - Avari
Taifa of Badajoz - Batalyaws (I've decided not to call these factions "taifas," because it's a bit anachronistic)
Taifa of Barcelona - Barshiluna
Duchy of Bavaria - Ducatus Bavariae
Duchy of Benevento - Ducatus Beneventum
Bohemia - Beheima
Kingdom of Brittany - Regnum Brittonum
Duchy of Burgundy - Ducatus Burgundiae
Kingdom of Carloman - Regnum Carlomanni
Kingdom of Charlemagne - Regnum Caroli (No magnus here
)
Kingdom of Connachta - Cóiced Ol nEchmacht
Emirate of Cordoba - al-Andalus
Duchy of Croatia - Regnum Croatorum (Latin again. Even the modern Croatian sources I found say that this was the name on inscriptions and things)
Kingdom of the Danes - Danir
Eastphalia - Ostfalahi
Duchy of Frisia - Freisias (this one might be anachronistic. Might be too old. I can just put it in Latin if that's the case)
Duchy of Gascony - Ducatus Wasconiae (yeah, W. Medieval Latin isn't great, and I think that Wasconia was the name)
Kingdom of Glywysing - Gulat Glywysing (if you think Old Irish is hard to find, Old Welsh is even worse. Found the word for "kingdom," but not much else. Most Welsh factions have modern spellings for their names)
Emirate of Granada - Garnata (way too early to be calling them an emirate I think)
Kingdom of Gwynedd - Gulat Guynet
Kingdom of Kent - Cantaware Rice
Kingdom of Leinster - Cóiced Laigin
Kingdom of Lombardy - Regnum Langobardorum
Kingdom of Mercia - Miercna Rice
Kingdom of Munster - Cóiced Muman
Nordalbingia - Didn't change this one. Again, need a source for Old High German I think.
Kingdom of Northumbria - Norþymbra Rice
Obodrites - Obotriti
Duchy of Pamplona - Ducatus Pompaeli (using the Latin name for the city, though again maybe anachronistic)
Papal States - Status Pontificius
Picts - Cruithentúath (think this is modern Gaelic, so maybe there's a better word)
Kingdom of Powys - Gulat Powys
Duchy of Provence - Ducatus Provinciae
Taifa of Sevilla - Ishbiliya
Theme of Sicily - Thema Sikelias
Duchy of Spoleto - Ducatus Spolitae
Taifa of Toledo - Tulaytula
Kingdom of Ulaid - Cóiced Ulaid
Taifa of Valencia - Balansiyya
Republic of Venice - Venetia (decided not to add "republic," but maybe I should)
Kingdom of Wessex - Westseaxna Rice
Westphalia - Westfalahi
Wilzi - Welatabi
Taifa of Zaragoza - Saraqusta