Three sisters Three Queens by Philippa Gregory

When Henry the seventh came to the throne of England, it's the reign of the Tudors that starts. 

He has two sons, two daughters.

The first son, Arthur gets married with a Spanish princess, Katherine, but he quickly dies, leaving a widow nobody cares for.

After the death of the king, the second son, Harry, becomes king under the name of Henry VIII th and he marries Katherine of Aragon who becomes Queen of England.

Margaret Tudor is married to James of Scotland, and becomes Queen of Scotland. But after the death of her husband, her life becomes erratic, running away, coming back, as she marries a scot, and it won't be her best decision!

Mary Tudor, marries the king of France, Charles XII th who dies soon, and the remarries with a young man.

Three queens, their jalousies, their adventures, their letters, told by Margaret, who is conceited and doesn't inspire any empathy, she's so boring.... so attached to traditions.

I succeeded to finish the book, but I had a hard time....