A Harlot's Progress, is of Gabrielle d'Estrees by Roman artist Lavinia Fontana. The portrait is most often dated 1599, which was the year then twenty eight year old Gabrielle died in April.
Gabrielle was the mistress of King Henri IV of France and her beauty was legendary. Her untimely death threw Henri into a funk that lasted the rest of his life. She is the subject of this scandalous and possibly posthumous double portrait, said to depict she (on the right) and her sister. In the painting, Gabrielle is holding Henri's coronation ring, which he gifted her in place of an engagement band.
Lavinia was born in Bologna but lived most of her life in Rome. She was famous in her own right, to some degree simply because of her gender. The Tudor Era on tumblr also attributes this stunning painting to Fontana.