As any true fan of AHS would know, every season of the show is connected in some roundabout way or another, but it can be difficult to keep track of how all the characters and seasons fit together. So, naturally, Ryan and Greg got together to create a timeline explaining how everything from season one through nine, is connected.
Even if you're an AHS expert, you might learn something from seeing the timeline laid out chronologically and paying attention to which events coincide. For example, did you ever notice that Edward Phillipe Mott (ancestor of Dandy Mott) built the Roanoke house around the same time that Madame Delphine Lalaurie was born? Or that Charles Montgomery built the Murder House only a few years before the Coven witches killed the Axeman murderer? Or that Kai and Vincent's parents die in a murder suicide the same year that Fiona Goode dies?
The seasons also directly interconnect in interesting ways, like how the stowaway who was essentially responsible for the mystical properties of the Roanoke colony was also the very first Supreme, which suggests that witches get their powers from "the old gods." Or how Malory uses "tempus infinitum" to change events that took place in season one, thereby altering the entire timeline. Who knows what kinds of mysterious consequences this could have.
If you want to much more detail about the AHS timeline, or you just want to see the whole thing laid out, check out Ryan and Greg's complete timeline for seasons one through eight above.