Forget your One Million Years Dungeons, Charlemagne DLC really does add 100 years to the game, adding the total up to almost 700 years of historical gameplay.

Crusader Kings II is the most complex title that Paradox Interactive, a company known for the depth of its releases, has ever created and the already impressive mods released for it, the best of which is the one based on A Song of Ice and Fire, will certainly find new ways to expand it in the future.

It's good, but yet another dramatic tale of intrigue in a game already packed with them. [Feb 2015, p.77]

It’s far from an essential purchase, but hardcore Crusader Kings 2 fans will probably want to pick this up for the custom kingdoms alone. For everyone else I’d advise giving it a miss unless you’re very interested in the period setting.