How many sonnets did Shakespeare write? Who is believed to be the "Dark Lady" of the sonnets?

Shakespeare did write 154 sonnets. In someone of them he speak about the "Dark Lady". Some scholars believe that she could be one of three historical women: Mary Fitton, a lady in waiting to Queen Elizabeth; Lucy Morgan, a brothel owner and former maid to Queen Elizabeth; and Emilia Lanier, the mistress of Lord Hunsdon, patron of the arts. Some also consider William Davenant's mother to be the Dark Lady.