were so fond, became a favourite motive for the Renaissance mantelpiece.  The classical amoretti, of which many versions in bronze existed, were also frequently copied.  But there was one radical difference between the children of antiquity and those of the Renaissance.  Though children were introduced on to classical sarcophagi and so forth, it is impossible to say that it was for the sake of their youth.  There are genii in plenty; and in the imps which swarm over the emblematic figure of the Nile in the Vatican the sculptor shows no love or respect for childhood.  There is no child on the Parthenon frieze, excepting a Cupid, who has really no claim to be reckoned as such.  Donatello could not have made a relief 150 yards long without introducing children, whether their presence were justified or not.  He would probably have overcrowded the composition with their young forms.  Whether right or wrong, he uses them arbitrarily, as simple specimens of pure joyous childhood.  Antique sculpture, too, had its arbitrary and conventional adjuncts—­the Satyr and the Bacchic attendants; but how dreary that the vacant spaces in a relief should have to rely upon what is half-human or offensive—­the avowedly inhuman gargoyles of the thirteenth century are infinitely to be preferred.  Donatello was possessed by the sheer love of childhood:  with him they are boys, fanciulli ignudi,[141] very human boys, which, though winged and stationed on a font, were boys first and angels afterwards.  And he overcame the immense technical difficulties which childhood presents.  The model is restive and the form is immature, the softness of nature has to be rendered in the hardest material.  The lines are inconsequent, and the limbs do not yet show the muscles on which plastic art can usually depend.  Nothing requires more deftness than to give elasticity to a form which has no external sign of vigour.  So many sculptors failed to master this initial difficulty—­Verrocchio, for instance.  He made the bronze fountain in the Palazzo Pubblico, and an equally fine statue of similar dimensions now belonging to M. Gustave Dreyfus.  Both have vivacity and movement, but both have also a fat stubby appearance; the flesh has the consistency of pudding, and though soft and velvety in surface is without the inner meaning of the children on the Cantoria.  In this work, where Donatello has carved some three dozen children, we have a series of instantaneous photographs.  Nobody else had enough knowledge or courage to make rigid bars of children’s legs:  here they swing on pivots from the hip-joint.  It is the true picture of life, rendered with superlative skill and bravura.  But Donatello’s children serve a purpose, if only that of decoration.  At Padua they form a little orchestra to accompany the duets.  The singing angels there are among the most charming of the company; and whether intentionally or not, they give the impression of having forgotten the time, or of being a little puzzled by the music-book!