Vana' diel has a long and rich history that SE has accumulated and it will enhance your RP experience to know some of it at least. That doesn't mean you should know everything or be able to recite it by heart but you should at least know enough to make your character's life and background more believable.
Why know It?Using a bit of history in your character's background can help you fill out the little details that add a nice touch making your character that much more of an individual.
As an example, If you're character was supposed to have grown up in Windurst during the crystal war how much more will your character telling the history mean if you can name the battle in which your older brother died?
As you can see, depending on your character's background, doing a little research on history might be a great idea. Not only that you might just end up RPing with another character with that shared event who does know and might leave you at a loss for words.
Tips to Enhance Your RP1) Know the basic history of your character's nation of origin and something about the people who lead it.
2) If you intend to say your character spends a lot of time in the past via the maws or experienced the Crystal War learn something about it.
3) If you're supposed to have a long family line figure out what "Age" it began and maybe pick a story per "Age" to lend some weight to being a proud new generation of that ancestor.
4) Understand tthe origins of your race and its historic rivalries and it will help maybe give you ideas as to what you can do with your characters attitudes about the other nations.
5) Understand that there is a an "official" myth on the origin of all the races and an actual history that is revealed in various storylines in the game. PLEASE BE COUTEOUS TO OTHERS AND AVOID REVEALING WHAT COULD BE A SPOILER WITHOUT ASKING IF THEY MIND YOU USING A HISTORIC BIT FIRST.
LinksThe following are links to other websites, articles and posts that will help you explore the history of Vanadiel.
Myth Vs Actual Vana'dielian HistoryThis post explains how the expansions actually enhance the knowledge of Vana's past and what an average citizen verses the historian should know.
Ages of Vana' dielian HistoryThis is from SE's official Website and contains what the average Vana d'ielian should know.
TimelineHere is a great source placing historical events and personalities in the ages Vanadielian dates. This is a great way to understand how the history of the different nations crossed paths with the others.