Just further breaking down the 533 Years of the Twlight Years.
The Twilight Years serve as an overarching Epoch on the Imperial Calendar. This is further divided into Periods and they are as follows.
Age of Blood
Age of Fires
Age of Lovers
Age of Steel -- Current
The Age of Blood
The Age of Fires
The Age of Lovers
The Age of Steel
The current Age in the Twilight Years.
The Present Date
Events, Wars and Fun Times in the Free Holds
Events, Wars and Fun Times in the Imperium.