I see Vlandia as being the Kingdom of the Franks, which at the Treaty of Verdun, split into three different sections,which would then go on to form The Kingdom of France (West Frankia) and The Holy Roman Empire and Northern Kingdom of Italy (Middle Frankia, East Frankia) The same way The Vlandians grew and then split into Swadians (France) and Rhodoks (HRE + Italy). The Battanians are more influenced on Welsh, Pict, and Anglo-Saxon Celts. Although I do see a bit of Ostrogoth and Visigoth inspiration in their late troop tree. The Holy Roman empire and Italian states were more known to use crossbows and pikes.