The connection between Queen Elisabeth II and the Portuguese royal
"The first blood tie is with King Afonso Henriques, whose descendant Eleanor of Castile married Edward I. Then Afonso IV of Portugal (son of the troubadour King Dinis and of the Queen Saint Elisabeth of Aragon), was great-gradfather of the Infanta Isabel of Castile who married Edmund of Langley, duke of York, who himself had Portuguese blood, being a descendant of the afforsaid Edward I.
Edward IV of England was a great-grandson of duke Edmund and his daugther married Henry II, the first Tudor monarch (also a descendant od Edward I) and so the line reaches James VI of Scotland and first of England, ancestor in the eleventh degree of the present sovereign.
Nuno Álvares Pereira, constable of Portugal in the beginnings of the 15th century, a hero and a holy man, is an ancestor of all European sovereigns. So, through his descendants, links up with Spain, Holy Roman Empire (House of Austria), Saxony, etc., and in due course with George III.
King João I of Portugal is also an ancestor of George III. This King of Great Britain was the grandfather of Queen Victoria, great-great-grandmother of Queen Elisabeth II.
The Duke of Edinburg, being also a great-great-grandson of Queen Victoria, has in his turn, this and other blood ties with Portugal."
Francisco de Simas Alves de Azevedo, do Instituto Português de Heráldica, Lisboa MCMLVII