We all know that Mary Stuart was beheaded at Fotheringhay on 8 February 1587 and that the Spanish Armada sailed to facilitate a Catholic invasion of England in the following year, leaving Lisbon on 28 May and fighting naval battles in late July, at Plymouth and Portland. The traditional view is that Mary Stuart’s execution and Elizabeth I’s support for the revolt in the Spanish Netherlands provoked Phillip II’s wrath.
It is quite possible that this was not the case and that Phillip had
sought to overthrow his quondam sister-in-law much earlier. Mary, as the daughter of Marie de Guise and widow of Francis II was the French-backed Catholic candidate for the English throne and Franco-Spanish rivalry ensured that Phillip, great nephew of Catherine of Aragon and a Lancastrian descendant proper+, would not act in concert with any of her plots; however her death cleared the way for him, especially as the French Wars of Religion were still to resolve themselves.
We can compare this with the England of 1685-8, as William of Orange allowed the Duke of Monmouth to attempt an invasion first and only asserted his stronger semi-marital claim against James VII/II afterwards. In 1483-5, by contrast, the Duke of Buckingham was legitimately descended from Edward III when he rebelled against Richard III, only for Henry “Tudor”, of dubious lineage, to benefit.
h/t Jeanne Griffin
+ See The Wars of The Roses, Ashdown-Hill, part 4.