ow but little.[97] At that time his
faculty had attained full maturity, and he produced the groups of dancing
children and choristers intended for the organ gallery of the Duomo.
Wholly free from affectation, and depending for effect upon no merely
decorative detail, these bas-reliefs deserve the praise bestowed by Dante
on the sculpture seen in Purgatory:[98]--

Dinanzi a noi pareva si verace,
Quivi intagliato in un atto soave,
Che non sembrava immagine che tace.

Movement has never been suggested in stone with less exaggeration, nor
have marble lips been made to utter sweeter and more varied music. Luca's
true perception of the limits to be observed in sculpture, appears most
eminently in the glazed terra-cotta work by which he is best known. An
ordinary artist might have found the temptation to aim at showy and
pictorial effects in this material overwhelming. Luca restrained himself
to pure white on pale blue, and preserved an exquisite simplicity of line
in all his compositions. There is an almost unearthly beauty in the
profiles of his Madonnas, a tempered sweetness in the modulation of their
drapery and attitude, that prove complete mastery in the art of rendering
evanescent moments of expression, the most fragile subtleties of the
emotions that can stir a tranquil spirit. Andrea della Robbia, the nephew
of Luca, with his four sons, Giovanni, Luca, Ambrogio, and Girolamo,
continued to manufacture the glazed earthenware of Luca's invention. These
men, though excellent artificers, lacked the fine taste of their teacher.
Coarser colours were introduced; the eye was dazzled with variety; but the
power of speaking to the soul as Luca spoke was lost.[99]

After the Della Robbias, this is the place to mention Agostino di Gucci or
di Duccio,[100] a sculptor who handled terra-cotta somewhat in the manner
of Donatello's flat-relief, introducing more richness of detail and aiming
at more passion than Luca's taste permitted. For the oratory of S.
Bernardino at Perugia he designed the facade partly in stone and partly in
baked clay--crowded with figures, flying, singing, playing upon
instruments of music, with waving draperies and windy hair and the ecstasy
of movement in their delicately modelled limbs. If nothing else remained
of Agostino's workmanship, this facade alone would place him in the first
rank of contemporary artists. He owed something, perhaps, to his material;
for terra-cotta has the charm of impro