The difficulty in painting the Madonna is complicated when the Infant Christ is introduced, because of the liability of the Child to interfere with a fine presentation of her figure. A similar problem was met with by the early Greeks, and doubtless they dealt with it in their paintings as in their sculptures, a few of which, showing an adult holding a child, have come down to us. These represent the child reduced in size as far as possible, and carried at the side of the adult figure.[a] A like system was followed by most of the Byzantine workers, and it is very noticeable in some of the fine French sculpture of the thirteenth century.[b] In the same period Giovanni Pisano in sculpture,[c] and Cimabue in painting,[d] maintained the tradition in Italy, and in the century following, Giotto,[e] Duccio,[f] Lorenzetto,[g] and others, often adopted the plan. Towards the middle of the fifteenth century, the relative importance attached to the Child in the group generally increased, and by the end of it, the old practice had been almost entirely abandoned. Meanwhile the artists had some hard problems to meet. The first was as to the size of the Child. It appeared to be generally agreed that an older Child should be represented than had been the custom, though a few artists held back, notably Fra Angelico, while in sculpture, Donatello maintained his habit of moulding the Child as only a few weeks old. With an increased age of the Child, the difficulty of securing repose for the group was enhanced, for it seemed to be proper with a child past its infancy, that it should be pictured as engaged in one of the charming simple actions common to childhood. These questions were settled in different ways according to the genius and temperament of the artists. A few of them, as Mantegna,[h] Lorenzo Costa,[i] and Montagna,[j] gave the Child an age of two years or more, and in some of their designs the figures seem to be of equal significance, Mantegna and Montagna in several examples actually standing the Child in the Virgin's lap with the heads touching each other. [a] See the Olympian Hermes of Praxiteles, and Irene and Pluto after Cephisodostus at Munich. [b] Groups in the Southern and Western porches of Amiens Cathedral. [c] Madonna and Child, Arena Chapel, Padua. [d] Groups at the Florence Academy and the Louvre. [e] Florence Academy. [f] National Gallery, London. [g] San Francisco, Assisi. [h] Madonna and Angels, at Milan, and other works. [i] Coronation of the Virgin, Bologna. [j] Enthronement of the Virgin, Brera, Milan.