This refers to the conception of the Virgin Mary without stain of Original Sin in the womb of her mother Saint Anne. It was the subject of much debate between the Franciscans, who commissioned altarpieces in support of it, and the Dominicans, who contested it. According to some medieval cycles of the life of the Virgin, Mary was miraculously conceived by an embrace, a moment represented in paintings showing the meeting of Joachim and Anne (the Virgin's parents) at the Golden Gate of Jerusalem. This theory was not adopted by the church, but the idea of her purity gained strength and Pope Sixtus IV gave his approval to the doctrine of the Immaculate Conception in 1475. Crivelli's painting of 'The Immaculate Conception' in the National Gallery, may be the earliest altarpiece specifically devoted to this subject, but an earlier altarpiece shows the Virgin and Child surrounded by narratives connected with the Feast of the Conception.
It enjoyed its greatest popularity as a subject for painting in the17th century, particularly in Seville in Spain, but it was not officially declared a dogma by the Catholic Church until 1854.
The term is sometimes mistakenly thought to refer to the conception of Christ. This is represented in art as the Annunciation.