Amateur historian Maike Vogt-Luerssen believes that she has discovered the true identity of the Mona Lisa, claiming in her book Who is Mona Lisa?: In Search of Her Identity (published in Germany) that she is Isabella of Aragon, Duchess of Milan and known friend of Da Vinci and not the Marquese del Giocondo, as is usually believed.
'Was da Vinci's lover the face of Mona Lisa?' by Tim Cornwall. The Scotsman, Saturday 26 June 2004. (Requires free site registration).