I have a question that I haven't been able to find an answer to on the wiki. In all circumstances I know of, there's always some specific instigation which triggers an alliance. What specific event(s) caused the 3 factions below to form?

Ebonheart Pact = ?

Daggerfall Covenant = ?

Aldmeri Dominion = ?


Thanks

P.S.--I am not looking for general, vague answers (unless that is the official answer lol) but specific things which prompted the formation of the unions.

Well, the wiki won't ever help you. You should go directly to the source; the TES:O website.

In any case:

Ebonheart Pact: the alliance was the result of the invasion of the Akaviri Kamal, who sacked Windhelm and then invaded Morrowind before being defeated at Red Mountain by the combined armies of Almalexia, Wulfharth, Vivec, and Jorunn Skald-king. They're invading Cyrodiil because they perceive Molag Bal as an existential threat to Nirn.

Daggerfall Covenant: Seems to be the result of a human endeavor to manufacture stability in the interests of trade and to ultimately revive the Empire in the wake of the chaos throughout Tamriel. They're invading Cyrodiil because the Aldmeri Dominion is, and want to prevent the Dominion from seizing White-Gold.

Aldmeri Dominion: According to older lore, the Dominion was formed after the Summerset Isles staged a coup in Valenwood (which was in chaos) and restored order by creating the Thalmor, a puppet governing body to rule over Valenwood. Although whether this is still true for this Dominion is unknown, since the events in question obstensibly took place after the events of TES:O. In any case, they're invading Cyrodiil now (according to TES:O) to end the chaos there and reclaim White-Gold (one of the mystical elven towers) as their own.

During the last invasion from Akavir the Nords, Dunmer, and Argonians joined forces to push them out of Tamerial, thus forming the base for the Ebonheart Pact.

In an effort to bring trade back to their lands the rulers of Hammerfell and High Rock have allied. The Orcs are fighting for them because they have promised to recognize Orsinium as an independent province.


During a Bosmer civil war one faction offered part of Valenwoods territory to some folks in Colovia prompting the Altmer to step in and keep Valenwood whole. They founded a joint council of Altmer and Bosmer in the after math that would be the governing body of the Dominion. Elsweyr would later join after the Altmer saved many lives from the Knahaten Flu.

Also, there was a marriage between the High King of High Rock and a Daggerfall princess.
Im hazy on the details but I think that a failed assasination attempt allowed the king to rally Hammerfell to his cause.
The Orcs are in it because they have been promised that Orsinium would become a recognised Imperial territory, with all the rights that entails.