The Nativity of Mary is a Roman Catholic and Anglican feast on September 8 that celebrates the birth of the Virgin Mary.
Nobody knows when the Virgin Mary was born. The traditional date is nine months after the Immaculate Conception on December 8.
Church tradition normally commemorates the death of saints. Only the Virgin Mary and Saint John the Baptist are honored with birthday celebrations.
The Birth of Mary by Giotto
The image of the birth of Mary is by Late Gothic/Proto-Renaissance Florentine painter Giotto di Bondone. He was the leading Italian artist of his day.
At a time when stylized Byzantine forms were in favor (El Greco was trained in Byzantine style), Giotto painted from life. He influenced the Italian Renaissance painters who came after him.
Giotto paintings are immediately recognizable. There is a flatness to the backgrounds and figures that almost looks like a theatrical scene, a pop-up book, or a computer screen.