Contemporary medieval records indicate that King Henry VI of England
was related to King Alfonso V, King of Aragon [Reference: Thomas
Rymer, Foedera 11(1727): 18 ([Alfonso V], King of Aragón styled
"cousin")].
Were King Henry VI of England and King Alfonso V of Aragaon related
within the 5th degree on at least one side. Answer: Yes, they were.
Below please find a chart which shows King Henry VI and King Alfonso
V's common descent from Fadrique II, King of Sicily (died 1337). The
chart indicates the two kings were related in the 5th degree of
kindred (that is, 4th cousins).
Fadrique II, King of Sicily
__________________/_________________
/ /
Isabelle/Elizabeth of Sicily Pedro II, King of Sicily
=Stephen II, Duke of Bavaria /
/ /
Stephen III, Duke of Bavaria Leonora of Sicily
/ = Pedro IV, King of Aragon
/ /
Isabeau of Bavaria Eleanore of Aragon
= Charles VI, King of France = Juan I, King of Castile
/ /
Katherine of France Fernando I, King of Aragon
=Henry V, King of England and Sicily
/ /
Henry VI, King of England Alfonso V, King of Aragon