Matthew Surridge wrote:
(1a. There's a mention in the book of the House of Buckingham ruling for 450 years, which implies that British history looks pretty different. Which is interesting since the Duke of Buckingham in the late 17th Century was a dabbler in alchemy. So hmm.)
So the Buckinghams come to power about 450 years ago. That means 1569. During Queen Elizabeth's Reign.
What happens in 1569? Northern nobles revolt and try to put Mary, Queen of Scots on the throne. In the real world, they fail. In this world, they defeat Elizabeth, behead her, and install Mary. James VI inherits the throne on her death, still, but various small changes cascade, ending up with a royal family named Buckingham by the present.