Ionic, or Corinthian being placed apart; and such was the effect of his zeal in that study, that he became capable of entirely reconstructing the city in his imagination, and of beholding Rome as she had been before she was ruined. But in the year 1407 the air of the place caused Filippo some slight indisposition, when he was advised by his friends to try change of air. He consequently returned to Florence, where many buildings had suffered by his absence, and for these he made many drawings and gave numerous counsels on his return. "In the same year an assemblage of architects and engineers was gathered in Florence, by the Superintendents of the works of Santa Maria del Fiore, and by the Syndics of the Guild of wool-workers, to consult on the means by which the cupola might be raised. Among these appeared Filippo, who gave it as his opinion that the edifice above the roof must be constructed, not after the design of Arnolfo, but that a frieze, fifteen braccia high, must be erected, with a large window in each of its sides: since not only would this take the weight off the piers of the tribune, but would also permit the cupola itself to be more easily raised." The obstacles appeared so insuperable to the Superintendents and the Syndics, that they delayed the execution of the cupola for several years. In the meantime, Filippo secretly made models and designs for his cupola, which perpetually occupied his thoughts. He boldly asserted that the project was not only practicable, but that it could be done with much less difficulty and at less expense than was believed. At length, his boldness, genius, and powerful arguments, brought many of the citizens to his opinion, though he refused to show his models, because he knew the powerful opposition and influences he would have to encounter, and the almost certain loss of the honor of building the cupola, which he coveted above everything else. Vasari thus continues his admirable history: "But one morning the fancy took him, hearing that there was some talk of providing engineers for the construction of the cupola, of returning to Rome, thinking that he would have more reputation and be more sought for from abroad, than if he remained in Florence. When Filippo had returned to Rome accordingly, the acuteness of his genius and his readiness of resource were taken into consideration, when it was remembered that in his discourses he had showed a confidence and courage that had not been found in any of the other architects, who stood confounded, together with the builders, having lost all power of proceeding; for they were convinced that no method of constructing the cupola would ever be found, nor any beams that would make a scaffold strong enough to support the framework and weight of so vast an edifice. The Superintendents were therefore resolved to have an end of the matter, and wrote to Filippo in Rome, entreating him to repair to Florence, when he, who desired nothing better, returned very readily.