Conversation so far:
What was Buckingham's rebellion in 1483 about?
Buckingham's rebellion was a failed but significant uprising, or collection of uprisings, of October 1483 in England and parts of Wales against Richard III of England.
Who started the conspiracy leading to Buckingham's rebellion in 1483?
In 1483, a conspiracy arose among a number of disaffected gentry.
Why was there a conspiracy leading to Buckingham's rebellion in 1483?
It is possible that they planned to depose Richard III and place Edward V back on the throne.
What did the gentry hope to accomplish leading to Buckingham's rebellion in 1483?
Buckingham proposed that Henry Tudor should return from exile, take the throne and marry Elizabeth of York, elder sister of the Tower Princes.
Who was Edward V of England?
Edward V succeeded his father, Edward IV, as King of England and Lord of Ireland upon the latter's death on 9 April 1483.

Question: So who would take the throne then?
Self-contained rewrite: Who would take the throne after Edward V was declared an illegitimate heir?