The Classic World of Darkness is the setting for White Wolf's series of Storyteller games of gothic horror. Whereas the core games were all placed in a modern day setting, a number of RPGs and associated books were given historical settings in the same world.
This setting covers three distinct sets of books that, although geographically distinct, are close enough in time that there can be interactions between them:
The World of Darkness setting of 1197 is a darker mirror of the real Dark Ages. Vampires and werewolves walk amongst humanity, strong with supernatural power. But this is also the time of the Long Night, when Christian hunters work together in the name of God to destroy these abominations. The original Vampire: The Dark Ages and Werewolf: The Dark Ages are set in this time period.
By 1230, the World of Darkness has seen an end to the Long Night. But now the War of Princes rages across Europe. Vampires, divided by class and moral outlook, fight for power and control in a conflict that is escalating and threatening to overwhelm their complex society. This is the revised Dark Ages setting, for such titles as Dark Ages: Vampire, Dark Ages: Werewolf, Dark Ages: Mage, Dark Ages: Fae, and their opponents in Dark Ages: Inquisitor.
In 1242, the War of Princes still continues. The Mongol army is moving across Europe. The Holy Roman Empire stands to war with the Papacy. The second Lombard League wields the word of the Pope and fights off Frederick II. This is the Dark Ages setting used in the Twentieth Anniversary edition of Vampire: The Dark Ages.