In Skyrim, what caused the Great Collapse that sent most of the city of Winterhold into the ocean is never revealed, but it might have been accidentally destroyed by the protagonist, the Dragonborn. The theory might seem implausible at first, but it's not an impossibility, and may be more credible than it appears at first glance. Developer Bethesda has neither confirmed nor denied it, and until they do, it's up to player interpretation.
The Great Collapse in Skyrim occurred in the year 4E 122, approximately 80 years before the start of the game. A series of powerful storms struck the town of Winterhold, leading to the swift erosion and collapse of most of the city into the Sea of Ghosts. Only a small part of the city survived, including the College of Winterhold, one of the most unique locations in Skyrim. Winterhold never recovered from the Collapse, leaving it a tiny town with little residents and less visitors. Since the College was left unharmed, many of the locals blamed its mages, along with its Dunmer refugees. According to the College, it was caused by the volcanic eruption of Red Mountain, yet this event occurred in the year 4E 5, over 100 years prior.
Most of the Dragonborn's interaction with Skyrim's Winterhold centers around the College of Winterhold questline, where they , learn magic, and eventually become the Arch-Mage, uncovering an ancient and powerful artifact known as the Eye of Magnus in the process. It quickly becomes unstable due to meddling from Thalmor agent Ancano, who goes mad and almost destroys all of Tamriel in his lust for power. The Eye of Magnus is key to the theory that the Dragonborn accidentally caused the Great Collapse during Skyrim's College of Winterhold storyline, along with a cryptic line by a member of the Psijic order, Nerien, who appears to the Dragonborn at the beginning of the questline.
How The Dragonborn Could Have Destroyed Winterhold In Skyrim
According to the theory, the Great Collapse was caused by the Dragonborn's interaction with the Eye of Magnus during the College of Winterhold questline. The basis is the cryptic warning given by the Psijic Order Monk, Nerien. "Know that you have set in motion a chain of events that cannot be stopped." It quickly becomes apparent what he's referring to: the Eye of Magnus, hidden deep within Saarthal. Over the course of the questline, the Eye is assaulted with magic by Tolfdir when it's first discovered, heavily scrutinized at the College, and has its power exploited by Ancano, so there are quite a few possible causes to make its power go out of control and cause a disaster that turned Winterhold into Skyrim's worst and most desolate city. If the Dragonborn is personally responsible, however, the most likely explanation may be them using the Staff of Magnus on the Eye, since it's the most significant and direct interaction they have with it, and with a considerably powerful magical artifact at that.
If the Dragonborn is not the direct cause of the Great Collapse, and it is instead the events surrounding the College of Winterhold storyline as a whole, then another explanation is that Ancano is actually responsible. He interacted with the Eye far more than the Dragonborn, and tampered with it greatly. This was the primary cause of the Eye growing unstable, according to the Psijic monks that appear to retrieve it after his death. He uses it to create a gigantic magical blast that kills Savos Aran, and unleashes an amount of strange magical wisps directly upon the town. Though they're hardly Skyrim's scariest or most horrific enemies, they do pose quite a threat until the Dragonborn destroys them with the help of their fellow College mages.
Arguments For The Dragonborn Destroying Winterhold In Skyrim
The theory of the Dragonborn's actions - or the events surrounding them - being the direct cause of the Great Collapse is a fascinating one. The Eye of Magnus is certainly powerful enough to cause most of Winterhold to fall into the sea. Ancano specifically says that while wielding it, he has "the power to unmake the world at my fingertips..." Whether this is an exaggeration is unknown, though it's likely not; a second Psijic monk, Quaranir, states that the Eye could destroy the world if it were left in the College. With this kind of power, causing a few storms is easily within the bounds of what the Eye of Magnus is capable of after the events at Skyrim's College of Winterhold left it unbalanced.
Although the Great Collapse occurred long before the Eye of Magnus was found, Elder Scrolls has proven that time is flexible in the world of Nirn. Alduin was sent forward in time by three Nordic heroes, Hakon One-Eye, Felldir the Old, and Gormlaith Golden-Hilt in the first era, and didn't reemerge until the fourth. A Wooden Mask can be used in Labyrinthian to see an ancient Dragon Priest altar in the past, and place more masks upon it to gain the final one. Two quests in Elder Scrolls Online utilize time travel as a mechanic, "Unearthing the Past" and "A Step Back in Time". There are also more significant examples, and ones that have been used to explain the multiple endings in Elder Scrolls 4: Oblivion; in three instances of Tamriel's recorded history, there have been events known as Dragon Breaks, which alter Elder Scrolls' history. They're complicated in of theory, but in essence they make it so that all the events of multiple split timelines become simultaneously true, even if they contradict one another.
Arguments Against The Dragonborn Destroying Winterhold In Skyrim
Although the theory of Skyrim's Great Collapse being caused by the Dragonborn and the events at the College of Winterhold is interesting, it also has its problems. There was no clear method of time manipulation used that would indicate that the events of the questline could influence Winterhold 100 years ago, and no Dragon Break was recorded to have occurred at that time. Given the lack of magic or artifacts specifically designed to travel through time, it doesn't seem like the Eye of Magnus or the Dragonborn could have influenced events that occurred so long ago - unless it's something to do with the Eye itself.
There's also no other evidence for the theory besides Nerien's words. He states that a chain of events has been put into place, but there's little else to the idea that Tamriel's timeline in Elder Scrolls was altered by the Dragonborn's actions at the College of Winterhold. This could, of course, be meant to reference the questline and the events that surround Ancano and his manipulation of the Eye of Magnus, and gives no inference that they are linked to the past other than seeming perhaps a bit conspicuously too portentous. Skyrim's Dragonborn has done a great many things, and while it may be impossible to prove that accidentally destroying the town of Winterhold is one of them, more light may be shed on the subject on future Elder Scrolls games.
