I'm interested in checking out Korean Historical Drama. I've never watched one before (unless you count "You who came from the stars").
How much Korean history should I know?
What would you folks recommend?
In comparison, as much as I love samurais, it took me a while to get into Japanese Historical/samurai drama because there was a lot I did not understand about history.
Thanks Panda! Do I need to know much about Korean history for the ones you recommended?
I started off Korean historical drama with Moon that Embraces the Sun..  Before that i didnt know there was a historical genre in Korean drama.. ;-)

Here's my list if historical drama that you can watch as a newbie... 

*Moon that Embraces the Sun 
*Sungkyunkwan Scandal
*Scarlet heart reyo
*Empress ki..  
*Splash splash love (only 2 episode special drama.   Really cute with time travel) 
*Faith (another time travel) 
*Hwarang
*Moonlight drawn by Clouds 

And you don't need to know much about the Korean history to watch theses dramas..  I started off with a clean slate and i understood almost everything...  Except for a few rules which i Googled or asked around..   Hope you enjoy some historical dramas..
I think often in dramas they explain some words that you might not know if you're watching only the dramas about nowadays. If anything, you can look it up on google and you'll find the answer pretty soon.

2 historical dramas I really enjoyed were Moon Lovers: Scarlet Heart Ryeo, which was a little bit modernized on the vocabulary part I think, and Mirror of the Witch -- which was my first historical drama and is still my most favorite one.

I am currently watching Rebel: The Thief Who Stole The People, and while it does take me some time to move forward with the episodes, I think it is also a very good historical drama.
There are a lot of good historical dramas out there. When I first started watching them I didn't know a thing about korean history either.
My favourites are:
-Moon Lovers: Scarlet Heart Ryeo
-The Princess' Man
-Dong Yi
-Empress Ki

I recommend you = Splash Splash LOVE, it's an excellent two episode drama, it has all the esencials!! you'll love it!!
Scarlet Heart Ryeo
The Princess Man'
Empress Ki
Six Flying Dragons
Iljimae
Thank you all for the suggestions and insight :D

Looks like I have a ton to watch this weekend lol

Some of these have tons of episodes :O
Warrior Baek Dong Soo 
Rooftop Prince 
Sungkyunkwan Scandal 
The Bridal Mask 
I'm liking Dong Yi so far.

Only gripe I have is the picture quality. It looks like a mid-day soap opera like Days of our lives xD

I also hope the Wardrobe quality (not looks, I have no problem with that) improves a bit. Overall, I'm liking it except for it looking like it was filmed as a soap opera lol.
Definitely Scarlet Heart Ryeo and Faith❤
Moonlight drawn by clouds or Sungkyunkwan Scandal  (Gender Bender)
Moon that embraces the sun (Rom)
Arang and the magistrate or Night Watchman's Journal (Ghost)
Mirror of the witch (Black magic/ curse)
Moon lovers (Time Travel)
(on air) Emperor master of mask or My sassy girl 
The three most badass female leads in historical drama:

Empress Ki
Queen Seon Duk
Queen Insoo
I second the notion on these:
Warrior Baek Dong Soo
Moonlight drawn by the clouds
Scarlet Heart Ryeo
Princess' Man
Rooftop Prince

I add:
Chuno
Shine or Go Crazy

 
The Princess' Man was the first one I saw and I never looked back. :3
I'd say a good one for beginner is Empress Ki. It has alot appeal similar to modern day dramas and the political intrigues were cleverly incorporated so the viewer didn't grow bored or annoyed by them so it was easy to fall in love with. One of the first historicals that I've ever watched that made me a die hard historical drama fan.

You don't really have to know any korean history besides a little bit about the caste system before watching it. I didn't know ANYTHING about korean history when I started but give it a few episodes and you get used to their culture, clothes, way of speaking, and social class system. I remember finding some things silly at first like their reactions to certain supposedly "shocking" things but then later having those same "shocking" things make more sense after becoming more accustomed to the culture. It took a while but the cultural shock eventually went away and alot of things in historicals that used to be weird will feel normal