Ivar the Boneless
Edward I established the Parliament in England.
King George III was ruler of the United Kingdom (which includes England).
Parliament was the ruler of England. But 4 the ruler of England during the Revolutionary War it was King George III.
The man-ruler referred to in Beowulf is King Hrothgar, the ruler of the Danes.
Elisabeth I.
George III
King Charles II was the ruler of England during the Great Plague of London in 1665.
Hrothgar is the King of the Danes that is helped by Beowulf, But he is descended from Scyld Sceafing. The term Danes come from the term Scyldings or Scyld danes. So the first Ruler of the Danes was Scyld Sceafing. The second was his son Beowulf the Dane.
King Charles II
I suppose the first great and remembered ruler of England was Henry II (Henry Plantagenet) in 1133 - 1189, this was mostly because of the vast Western European Empire he controlled.
Queen Victoria 1837-1901
King Henry