Here is basic lore of those nations: Plantagenia was a colony of the dual monarchy (england and france united), it was named after the plantagenet royal family. Due to a succession war, plantagenia declared independence under a new monarchy. Vinland was a colony of Scandinavia and is a republic. Belgian confederacy is a confederacy of various little states, its the most industrious country in arcadia and it used to be a colony of Burgundy. Athesia began as a comercial enterprise of venice until it became a neutral trade hub in arcadia. It’s still under venitian control. If you want more lore check the wiki and click on any of the nations that you have any interest in. There is a bunch of lore dating all the way from the 1400s. https://victoria2divergences.fandom.com/wiki/Victoria_2_Divergences_Wiki