“ The emperor, “of whose heart he held the keys,” as Dante says, sent him to Rome in 1232 and 1237 to negotiate with the pope, to Padua in 1239 to induce the citizens to accept imperial protection, to England in 1234–1235 to arrange a marriage between Frederick and Isabella, sister of King Henry III. He proved a skilful and trustworthy diplomat, and he persistently defended the emperor against his traducers and against the pope’s menaces. ”

“ Frederick, whose suspicions had been awakened by the slanders of the envious, had him imprisoned and blinded without giving him a chance to rebut his accusers. Unable to bear his disgrace, he committed suicide in his prison at Pisa in 1249. ”