The Cathedral at Florence had been carried out during the fourteenth century--_all but its cupola_--from the design of Arnolpho and his successors. A dome equal in space to that now existing was prepared for, but various causes delayed for a century its actual erection, so that, when it was at length undertaken, the prevailing style had changed. It is probable that Arnolpho intended to have sprung his dome at a far lower level, and to have made it like that of the adjoining baptistery; perhaps not exhibiting externally its domical form. Brunelleschi raised the drum to a considerable height, exhibited his dome as a vast external feature, and crowned it with a culminating lantern, thus giving us at once the leading features--and that on a scale never since exceeded--of what I have called the _modern_ type of dome. Had he made its details more accurately to harmonise with those of Arnolpho’s structure, his work would have been perfect. Not only is his dome erected on Gothic walls and arches, but its own section is a pointed arch, so that in all but its decorative features--and in these in some degree--it is essentially a Gothic dome. It is not, however, pendentive, nor is it circular in plan; and, though opening by arches into the arms of the cross, it is after all merely the covering of an octagonal chamber, so that its claims rest more on its size, its height, and its external beauty, than any novelty of development. Of its successors the name is legion. It would be useless for me to attempt to enumerate even the most successful of them. I will therefore content myself with a brief description of the two most typical--those of St. Peter’s, at Rome, and of our own St. Paul’s. I am not aware of any dome of great scale erected in the interval between Brunelleschi’s dome at Florence and that of Michael Angelo at Rome. The latter, however, was the crowning result of the efforts of successive architects, especially of Bramante and Sangallo. In one sense it does, and the other it does not, show evidence of this lengthened period of development. [Illustration: Fig. 452.--Section looking North, St. Peter’s, Rome. (_From Fergusson_).] Its unity of design would bespeak it as the work of one master-mind, while its perfection may mark it as the result of oft-repeated trials.