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His monument to Pope Gregory X. in the Cathedral of Arezzo, is ranked among his best works. “Browning possesses the ‘Crucifixion’ by M. to which he alludes, as also the pictures of Alesso Baldovinetti, and Taddeo Gaddi, and Pollajuolo described in the poem.” --Browning Soc. Papers, Pt. II., p. 169.