Margaret of Beaufort, the evil villainess of this story, was highly regarded as a saintly woman in her lifetime.
Edward Stafford Duke of Buckingham, and his brother, Henry Stafford Earl of Wiltshire, were cousins of Queen Elizabeth of York. Their mother Catherine Woodville was Elizabeth of York's aunt and the sister of Elizabeth Woodville.
After her husband dies Maggie Pole helps her two cousins Edmund De La Pole and George Neville overthrow the Tudors. Edmund was a real man who was her cousin (his mom and her dad were siblings) but George Neville could have been one of two men who were closely related to Maggie Pole. One died before Henry VII became King and the other never plotted against the Tudors and became an advisor to Henry VIII and was actually her son Henry's father in law.
In 1501, when Prince Arthur married Catherine of Aragon (officially in-person) Prince Henry was only 10 years old. When Elizabeth of York died, he was 11 and she was 16 years old.
Charlotte Hope and Ruairi O'Connor who play Catherine of Aragon and Henry VIII fell in love during production and are dating.