I've been a human RPer for a long time now (Almost three years) and have been part of various different governments. In the hope that I can answer some of your questions (And my apologies to experienced historians for the often over-simplified accounts):
-The current year is 1515.
-Start in Felsen. Everybody congregates generally in Felsen, the capital city of the main human Kingdom of Oren.
-There are a few different cultures which together make up the Heartlanders. They're generally accepted to be as follows:
-Savoyards, which make up the vast majority of Heartlanders. They're from the Duchy of Savoy (Its former capital the city of Aldersberg, its current capital the city of Felsen) and they've risen to prominence ever since their leader, King Olivier de Savoie, became king of Oren and of all the humans as a result. They constitute the dominant group in Oren and many of the noble families - de Savoie, de Bar, de Sola - are all Savoyard families. Savoyard culture is generally inspired by many continental western European cultures, including the French, Dutch, Italian and German cultures. Savoyards are often seen as overly cautious, decadent, greedy and prone to great intrigue and subterfuge by other humans, however they are also known for their economic and political acumen, patience, architectural style and organization.
-Renatians, which are just about extinct these days. When unified, royal Oren split under King Enor (Over 200 years ago in RP now) one of the kingdoms that it splintered into was the Kingdom of Renatus. That kingdom stood for a while until the King of Renatus, Godfrey I, unified humanity and crowned himself the first Emperor of Oren. Renatus has existing in various forms ever since, either as an independent realm or as a realm in fief to the Empire as a whole. The last time Renatus existed as an entity was roughly 35 IC years ago, when Maric Varodyr, the Count of Angren, led a rebellion against the Empire as he was dissatisfied with the Highlander-dominated politics at the time. He believed that Heartlanders were being discriminated against and marginalized, and he crowned himself the rebel King of Renatus, thus dismantling the Empire into five or so smaller countries. Renatus fell apart after a while after an undead assault, and the human realms were reunified by King Andrew (A Highlander Raev monarch, called Andrik by his people) however the Empire has not been restored since. There aren't many Renatians around any more, and many of them were slain and raised into undeath. Renatian culture is based on generic human fantasy culture, much like you'd see in many other franchises - the only real houses around that are considered to be Renatian are Varodyr and Horen, the latter of which have faced a sharp decline since their family lost the Imperial crown about 100 IC years ago.
-Salvites, from Salvus, who are not currently under Oren (The greater human realm) and exist as a rogue, independent state. When Oren split three ways under King Enor, aside from the Kingdoms of Renatus and Hanseti (A Highlander realm) there was also the Kingdom of Salvus. Salvus was an agrarian, mercantile realm known for its social liberation, democratic government and alien concepts of individual liberties - this made Salvites an often persecuted and unwelcome group within Oren. When Godfrey Horen unified humanity under the first Empire, Salvus was restored as a realm in fief to Oren - they quickly became a target of many other groups which would express their disdain, justified or not, for the realm in a multitude of ways. When the Horen dynasty lost control of Oren around year 1430, Salvus was abolished. It was recently reformed as a republic independent of the greater Oren realm. Salvite culture was always very bland and not necessarily inspired by anything, however as of late republican Salvus has taken a very ancient Romanesque inspiration. There are pretty much no humans in Oren proper who identify as Salvite.
-Auvergnians, from the former territory of Auvergne, who have been diminished in number for a while. They were very French-inspired, however Auvergne has not existed as an entity for nearly 100 IC years now. The de Sarkozy family (A formerly prominent family with a legacy felt throughout all of Oren) were of mixed Auvergnian, Savoyard and Highlander ancestry.
-Ilatians, who are very Italian-inspired and have never had a realm or land of their own. I don't know much about them other than they're pretty much extinct other than a few individual players who maintain the legacy.