Tempera on wood, 188 x 133 cm.
Museo dell'Opera del Duomo, Siena

On the bed is Mary's mother, St. Anne. The father, St. Joachim, is in the left panel receiving the news.  The church-like architecture makes a point about the Virgin but also helps to distinguish the composition from images of the birth of Christ, where the venue is a stable or cave.

More of Mary's birth, youth, and marriage.