The period began with the parliamentary recognition of the claim to
the crown of Henry, Duke of Lancaster, son of John of Gaunt, Duke of
Lancaster, fourth son of Edward III. By this act the claim of Edmund
Mortimer, a descendant of Edward III by his third son, Lionel, Duke of
Clarence, was deliberately set aside, and this change in the order of
succession eventually furnished an excuse for civil war.[1]
[1] Before the accession of Henry III, Parliament made choice of any
one of the King's sons whom it considered best fitted to rule. After
hat time it was understood that the King's eldest son should be chosen
to succeed him; or incase of his death during the lifetime of his
father, the eldest son of the eldest son; and so forward in that
line. The action taken by Parliament in favor of Henry IV was a
departure from that principle, and a reassurtion of its ancient right
to choose and descendant of the royal family it deemed best. (See
Genealogical Table, p. 140.)