The design for this stamp is taken from a terra-cotta sculpture by Andrea della Robbia. Andrea was a nephew of Luca della Robbia, a 15th-century Florentine Renaissance sculptor and founder of a famous enameled terra-cotta workshop. On Luca's death, Andrea took over the workshop and produced many altarpieces and devotional Madonnas. The workshop then passed to Andrea's sons. Critics do not believe that the successors of Luca della Robbia had his originality and most of the subsequent pieces were ably imitated.