There are 3 people it’s attributed to. But an entire book makes an excellent argument on why it’s Sofonisba, based on relationships and geographical likelihood.
From what I read, I’d also go with Sofonisba.
i used to like reading books about artists- picked up Van Gogh’s massive book with all his notes, letters, paintings and commentary by people like his brother, and others- was long book but really enjoyed reading it- such a fascinating character he was- tortured in mind, but truly a great artist in his own right- very cool read-