It had been for a long time a cherished wish of Galileo’s to have with him during the evening of his days his most devoted and favourite disciple, Father Castelli.[556] But the professorship which he held at Rome made the attainment of this wish difficult. As it was now supposed that a speedy death would deprive the world of the great philosopher, the Grand Duke requested through Niccolini at Rome that Castelli might come to Florence, for a few months at least, that he might yet receive from the lips of his dying master many ideas of importance for science, which he might not perhaps confide to any but his trusted friend.[557] After some difficulties were surmounted, he actually received the papal consent, but only on condition that a third person should always be present during the conversations with Galileo.[558] Early in October Castelli arrived in Florence, where the Inquisitor-General, as charged by the Holy Office, gave him permission to visit Galileo, with the express prohibition, _under pain of excommunication, to converse with him on the condemned doctrine of the earth’s double motion_.[559] The permission, however, to visit Galileo seems to have been very limited, for Castelli repeatedly wrote to Cardinal Francesco Barberini, with the most urgent entreaties to obtain an extension of it for him from the Pope. Castelli protests in this letter that he would rather lose his life than converse with Galileo on subjects forbidden by the Church. He gives as a reason for the need of more frequent interviews that he had received from the Grand Duke the twofold charge to minister to Galileo in spiritual matters, and to inform himself fully about the tables and ephemerides of the Medicean stars, because the Prince Giovanni Carlo, Lord High Admiral, was to take this discovery to Spain.[560] The cardinal replied that in consideration of these circumstances, Urban VIII. granted permission for more frequent visits to Galileo, under the known conditions;[561] but the official permission, was not issued until about November.[562] Nothing is known in history, however, of the Lord High Admiral’s having ever taken Galileo’s method of taking longitudes to the Peninsula.