Who is Laetitia Knollys from The Virgin's Lover and what is their importance?

Laetitia Knollys is the daughter of Elizabeth's cousin Catherine and Frances Knollys, who comes to be a hand maiden and courtier in Queen Elizabeth's court when Elizabeth attains the throne. Avowed Protestants, the Knollys had fled to Germany to escape persecution under Bloody Mary's reign, and return to wealth, position and power under the Protestant Princess.