Then moving down to the bottom-left corner of the scroll, we see the Tudor line leading to Queen Elizabeth I ("Elizabetha Regina") from Owen to Edmund to King Henry VII to King Henry VIII to Queen Elizabeth.
The legend of Arthur, "The Once and Future King," has played a significant role in more than one dynasty of Britain's monarchs. Keeping my focus on the Tudors, we will start with the founder of that dynasty, Elizabeth's grandfather King Henry VII.
Henry VII was the last British monarch to claim the crown by conquest. He did so by defeating King Richard III at Bosworth Field in 1485. As Henry marched into battle he did so under the white and green colors of the Tudors, but upon these colors he flew the red dragon. This symbol had also been used by Cadwalader, from whom Henry claimed descent. The red dragon was also a symbol of Uther and Arthur, both called Pendragon ("Chief of Dragons"), a metaphor for the High King of the Britons.
Henry's triumph at Bosworth proved to be the end of what we call the Wars of the Roses, civil war between the houses of Lancaster and York that had raged on and off for about 30 years. Though with our hindsight we know this to have ended the Wars of the Roses, the people of the time could not have known this. It didn't help that Henry's claim to the throne was quite tentative. It came through his mother's side. She was a great-granddaughter of John of Gaunt (who was one of the younger sons of Edward III), and this descent was through the illegitimate birth of a child to John and his mistress Katherine Swynford. So it was a claim based on the female line, a younger son of a monarch, and an illegitimate birth, yeah, that's a bit of a stretch . . .
Because of the recent unrest in the country and his own extremely tentative claim, Henry felt a need to legitimize his rule, and what better way to solidify one's claim to the throne than to be able to trace one's lineage back to King Arthur?!
Just as John Dee later drew up a genealogy for Elizabeth, Henry VII had his court genealogists draw one up for him that traced his lineage back to Camelot. The site of Camelot was at that time considered to be Winchester, so when Henry's wife was pregnant with their first child, Henry sent her to Winchester (i.e. Camelot) give birth. She had a son, and they gave him the name ARTHUR.
It seems this may have been tempting fate. Prince Arthur died in 1502 at the age of 15, seven years before he would have inherited the throne. His younger brother Henry inherited instead, becoming Henry VIII.
It seems that this theme of wanting to prove dynastic legitimacy continued throughout the Tudor line. Henry VIII had the round table (thought in that time to be Arthur's) in Winchester's Great Hall painted with the emblem of the Tudor rose in the center and with an image of Arthur seated and surrounded by names of the Knights of the Round Table . . . and looking a great deal like Henry himself. After all, it can't hurt to have proof of a family resemblance between one's-self and one's famous ancestor!
John Dee's work for Henry's daughter Elizabeth may have related to issues of the Tudor claim to the throne as well, but it went beyond that. Through various sources, including a letter from the famous cartographer Gerardus Mercator under whom he had studied, Dee believed that there had existed a wide-spread British Empire under King Arthur (and other Welsh rulers from whom the Tudors were descended such as Prince Madoc). This kingdom was supposed to have covered vast territory ranging from Greenland, Baffin Island and Labrador to New York to Frieseland to Normandy and Scandinavia.
During Elizabeth's reign, England had not gotten much of a foothold in the New World. In 1494, just over half a century prior to her reign, the Treaty of Tordesillas was signed, splitting between Portugal and Spain all newly-discovered lands outside of Europe. Dee's work, including a collection of manuscripts titled Brytanici Imperii Limites, was intended to show that England had prior claim by having gotten there first, with Arthur in 530 AD and Madoc in 1170 AD, both predating Christopher Columbus by quite a lot!
Dee is credited with being the first to use the term "British Empire." There is much more detail I could share, but perhaps I've written enough at this point - especially as, once I'm able to travel again, I'd like to include future posts on Dee's mathematics as used in the navigation of Drake, Raleigh, and others. I'll just end with the comment that by the time of the reign of another British queen, that of Victoria, the British Empire had become the largest in the history of the world. It covered so much of the globe, more than a fourth of the entire land mass of earth, that it became known as the empire on which the sun never set.