 The painting 's title dates to 1550 . An acquaintance of at least some of Francesco 's family , Giorgio Vasari wrote , " Leonardo undertook to paint , for Francesco del Giocondo , the portrait of Mona Lisa , his wife " ( Italian : Prese Lionardo a fare per Francesco del Giocondo il ritratto di mona Lisa sua moglie . ) . The portrait 's Italian name La Gioconda is the feminine form of her married name . In French it is known by the variant La Joconde . Though derived from Lisa 's married name they have the added significance that the name derives from the word for " happy " ( in English , " jocund " ) or " the happy one " . 
