Not a conspiracy, but related in that "authorship" as we know it did not exist until after it was no longer lethal to print pamphlets for or against the Sovereign - sometime, for the Anglo-American world, shortly after the American revolt. So authors conspired to hide their identities all the time.
I believe Shakespeare was De Vere ("Shakespeare" by Another Name by Mark Anderson if you want a good overview). My reasons: instability of authorship, comparison to known writing, decryption of the sonnets, especially the dedication, the frequent foreign travel, especially to Italy, of the two primary contenders (Neville being the other), the use of hendiadys, and the early use of developing English language words such as "refrigeration."
