When Would Edward V Have Reached Full Legal Majority

1) As has already been stated there was no fixed point for ending a minority - much depended on the character of the King and events.
2) A King's will after his death in relation to the government of the realm etc had no bearing in law. Usually a consensus emerged (which might reflect the dead King's wishes or not) in terms of how the realm was to be governed during any minority. In Edward IV's case there is no evidence that he appointed a Lord Protector or Regent that pre dates Richard's assumption of power, the will does not survive, his earlier will made during war with France seems to suggest no such arrangements. It was in Richard, Hastings and Buckingham's political interest to suggest that had been Edward IV's intention - to give their actions a legal and moral justification.

If I may ask, what were the details of Edward's earlier will? I ask, because I can only find mention that he made one, but not what the specifications were (plus I'd like to use an alt-version of it in my TL).

3) Richard II's minority allowed the king to exercise kingship with the help of a series of the council - effectively limiting the ability of his uncle's to govern in his name. Henry VI's minority saw a regency council created with his uncle as senior regent with the other uncle as Lord Protector. The consensus in 1483 seems to have been the council intended to govern in the King's name until the coronation at least, the Queen was praised for her moderation at the time between the two biggest rivals at court Hastings and her son Dorset. Hastings probably wanted to ensure that the new King was not dominated by his half brother (and Hastings step son in law) hence his initial support for Richard of Gloucester (aping the minority of Henry VI)....
5) Propaganda was a useful art throughout this period - there is very little real evidence that the Queen or her family by 1483 were a) deeply unpopular or b) any kind of power group at Edward IV's court in terms of competing with the enormous influence of Gloucester. Richard III like the Earl of Warwick a decade or so earlier used them and attacked them in order to justify his own actions - his previous relationship with the Queen, her surviving brothers and Dorset was pretty cordial.

I agree, if anything, from various sources I gather that it was more a case of headless chickens running around once Edward IV died than a Gloucester-York Party vs Queen-York party. Gloucester was certainly the most powerful landowner in England after the king, since he'd basically emerged after Clarence's execution as holding not only his wife's share of the Neville inheritance but the guardianship of his nephew, young Warwick's share too, so basically a Kingmaker II, and not someone you should piss off. If only the council hadn't thought Elizabeth Wydeville was overreacting when she wanted the army and the fleet secured for her son...
 
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