The theme of childhood has been used in art history to evoke a wide array of themes, from family life to personal histories and humanitarian concerns. Perhaps the most canonical representation of childhood in Western art is that of the Christ child with the Madonna, which appeared widely, beginning in the early Renaissance period. Diego Velázquez often included children in his portraits of the Spanish royal family, and beginning with Impressionism, childhood became a central theme in more intimate depictions of everyday life, ranging from Edgar Degas' dancers and Berthe Morisot's portraits to Mary Cassat's mother-and-child scenes. Jacob A. Riis often depicted children in his photographs of life in New York City tenements, in order to stir public empathy around their living conditions. In contemporary art, portraits of children figure in Taryn Simon's broad genealogical projects and Sally Mann's controversial photographs of her own offspring, while artists such as Mike Kelley and Paul McCarthy have probed the darker elements of childhood.