“The last truly legitimate King was Henry VI, who was much too kind and decent a man to hold onto his crown.”
Who inherited it from the son of Usurper Bolingbroke.
Really, the last legitimate king was Richard II, King of England, son of the black prince.
It’s best to understand things from the perspective of Edward III - everything revolves around him. The other important king is Charles I, oddly enough. Despite his execution, every one of his 5 children, were either King/Queen (in that order), or are the current senior heirs to the King of England.
Edward III
.Edward the Black Prince
..Richard II (Deposed and killed)
..Lionel of Antwerp Duke of Clarence
...Philippa of Clarence 5th Countess of Ulster
....Roger Mortimer 4th Earl of March
.....Edmund Mortimer 5th Earl of March (died of Plague)
.....Anne Mortimer Countess of Cambridge
......Richard Plantagenet 3rd Duke of York
.......Edward IV King of England
........Edward V King of England (killed in tower)
........Richard of Shrewsbury (killed in tower)
........Elizabeth of York Queen of England
.........Arthur Prince of Wales (died on marriage)
.........Henry VIII King of England
..........Edward VI King of England (died in teens)
..........Mary Tudor Queen of England (died without kids)
..........Elizabeth Tudor Queen of England (never married)
........Margaret Tudor Queen of Scotland
.........James V King of Scotland
..........Mary I Stuart Queen of Scots
...........James VI/I King of Scotland and England
............Henry Duke of Wales (Died of Typhoid)
............Charles I King of Scotland and England
.............Charles II King of Scotland and England
.............James VII/II King of Scotland and England
..............James Francis Edward Stuart (Test act)
...............Charles Edward Stuart
...............Henry Benedict Stuart
.............Henry Stuart Duke of Gloucester(smallpox)
.............Princess Mary of Orange (no kids)
.............Princess Anne of England (no kids)
.............Henrietta Marie of Orleans
..............Marie Louise of Spain (no kids)
..............Anne Maria Queen of Sardinia
...............Victor Amadeus Prince of Peidmont(smallpox)
...............Charles Emmanuel III King of Sardinia
................Victor Amadeus III King of Sardinia
................Charles Emmanuel IV King of Sardinia
.................Victor Emmanuel I King of Sardinia
..................Maria Beatrice of Savoy
...................Francis V Duke of Modena
...................Archduke Ferdinand of Austria
....................Maria Theresia Queen of Bavaria
.....................Rupprecht Crown Prince of Bavaria
......................Albrecht Duke of Bavaria
.......................Franz Duke of Bavaria (alive today)
TRUNCATING HOUSE OF SAVOY
...........Elizabeth of Bohemia
............Henry Frederick Prince Palatine (drowned)
............Charles I Louis Elector Palatine (no kids)
............Prince Rupert of the Rhine (no kids)
............Prince Maurice of the Palatine (drowned)
............Edward Count Palatine of Simmern (Test Act)
.............Luise Marie of Salm
..............Louis Otto Prince of Salm
...............Dorothea Agnes Princess of Salm
TRUNCATE HOUSE OF SALM
............Elizabeth of Bohemia (Nun)
............Louise Hollandine of Bohemia (unmarried)
............Henriette Marie of Bohemia (died young)
............Sophia Electress of Hanover
.............George I King of Great Britain
..............George II King of Great Britain
...............Frederick Prince of Wales
................George III King of Great Britain
.................George IV King of Great Britain
.................Frederick Duke of York (no kids)
.................William IV King of Great Britain (no kids)
.................Edward Prince of Kent
..................Victoria Queen of the United Kingdom
...................Edward VII King of UK
....................George V King of UK
.....................Edward VIII King of UK (abdicated)
.....................George VI King of UK
......................Elizabeth II Queen of UK
There’s a few other Plantagenet lines out there that are still in existence. The present lineage is the third most senior line, behind the Jacobins and the Salm branches.
Who inherited his crown by descent from the Conqueror, who won the throne by invasion and conquest.
Which leads us to the interesting question of how descending from a conqueror can provide a better title than being a conqueror yourself.
Richard II and Henry VI lose their thrones, and eventually their lives, because they were unable to hold onto the allegiance of a sufficient number of the political nation of their time.
We often think of hereditary monarchies as not having politics in the sense we think of them, but of course all leaders have to keep enough people on their side to maintain their power. No elections just means the political struggle isn't in the open, it doesn't mean it goes away.
During most of the absolute monarchy early modern period, the political struggle was carried on by who had control of the Guards, in sort of a modern version of the Praetorian Guards of the Roman Empire.
Seen most obviously in the Russian and Ottoman Empires, where losing control of the Guard often resulted in a dead monarch, but generally playing out in all the others.