Who is Robert Dudley from The Virgin's Lover and what is their importance?

Robert Dudley, son of the Lord Dudley the Lord Protector of King Edward, was a man who was accustomed to greatness. He grew up beside the kings and queens of England, at a time when the Dudleys were the second family of the realm and, for a short while, almost became the first. Robert Dudley has seen his father executed as well as most of his brothers, other brothers die in battle and the rest of his family flee England from their persecutors.