Anna selbdritt is a subject in Christian art, showing Saint Anne with her daughter, the Virgin Mary, and her grandson Jesus, literally "Anne herself the third," or if you will "Granny makes three." This type of depiction has been quite popular in Germany from the 14th century and is known as Anna te Drieën in the neighboring Low Countries or Metterza in Italy.
Read more about Anna Selbdritt: Mother and Daughter, Byzantine Iconography, See Also