receives the command to sheath the dagger already touching the
shoulder of his son. The naked boy is kneeling on his left leg and is
modelled with a good deal of skill, though, broadly speaking, the
treatment is rather archaic in character. It is a tragic scene, in
which the contrast of the inexorable father and the resigned son is
admirably felt. Donatello had to surmount a technical difficulty, that
of putting two figures into a niche only intended for one. His sense
of proportion enabled him to make a group in harmony with its position
and environment. It _fits_ the niche. Statues are so often unsuited to
their niches; scores of examples could be quoted from Milan Cathedral
alone where the figures are too big or too small, or where the base
slopes downwards and thus fails to give adequate support to the
figure. There is an old tradition which illustrates Donatello's
aptitude for grouping. Nanni di Banco had to put four martyrs into a
niche of Or San Michele, and having made his statues found it
impossible to get them in. Donatello was invoked, and by removing a
superfluous bit of marble here, and knocking off an arm there, the
four figures were successfully grouped together. The statues, it must
be admitted, show no signs of such usage, and Nanni was a competent
person: but the story would not have been invented unless Donatello
had been credited in his own day with the reputation of being a
master of proportion and grouping. Donatello, however, never really
excelled in the free standing group. His idea was a suite or series of
figures against a background, a bas-relief. The essential quality of a
group is that there should be something to unite the figures. We find
this in the Abraham, but the four martyrs by Nanni di Banco are
standing close together as if by chance, and cannot properly be called
a group in anything but juxtaposition of figures. Il Rosso helped to
make Abraham. The commission was given jointly to the two sculptors in
March 1421, and the statue was finished, with unusual expedition, by