John Lawrence Finnerty,
Catholic Encyclopedia
(1913)
“ This work afforded little scope to Fra Guglielmo's imaginative powers, but its masterly execution places him among the greatest artists of his time, second only to his master, Niccolo Pisano. On the other hand, the figures show some faultiness characteristic of the period in the stiffness and lack of finish in the extremities. They are also crowded into too narrow limits. ”

