Brunelleschi’s most important commission, however, was to provide the massive dome for the cathedral. Men had almost despaired of this ever being done, since the space to be crowned – 138 feet in diameter – was so great. But Brunelleschi, who had made a careful study of the Pantheon and other buildings in Rome, insisted that it could be executed perfectly well and without scaffolding. The committee appointed by the Masons’ guild to consider the problem were highly sceptical, particularly as Brunelleschi, petulant and ill-tempered as always, declined to explain to them how he intended to set about the task, insisting that the matter must be left entirely in his hands and that no board of untrained busybodies should be given the opportunity of interfering with his design. The story is told that at one of the committee’s inconclusive meetings, Brunelleschi produced an egg, announcing that only he knew how to make it stand on its end: when all the others had confessed their failure to do so, he cracked its top on the table and left it standing there. ‘But we could all have done that,’ they protested. ‘Yes,’ replied Brunelleschi crossly, ‘and you would say just that if I told you how I propose to build the dome.’ On a later occasion Brunelleschi became so obstreperous that the committee gave orders for him to be forcibly removed from their presence. Attendants seized him, carried him out of the palace and dropped him on his back in the Piazza. Thereafter people pointed him out to each other in the streets, shouting, ‘There goes the madman!’
Ultimately, after numerous other architects had been consulted and various ideas, such as a dome made of pumice-stone, had been rejected, the Committee gave way and in 1420 Brunelleschi was entrusted with the complicated task. To his exasperation, however, he was required to accept the collaboration of Ghiberti, whose assistance in the early stages was probably more useful to Brunelleschi than Brunelleschi would ever allow or posterity would recognize.
Sixteen years later the dome, as much an extraordinary feat of engineering as of architecture, was finished; and on 25 March 1436, the Feast of the Annunciation, the first day of the year according to the idiosyncratic Florentine calendar, it was consecrated in a splendid five-hour ceremony.10 A wooden walk, raised on stilts, hung with banners and garlands and covered by a scarlet canopy, was constructed between the Pope’s apartments in the monastery of Santa Maria Novella and the door of the Cathedral. At the appointed hour the Pope appeared, clothed in white and wearing his jewelled tiara, and began the slow procession along the carpet which had been laid over the raised boards beneath the canopy. He was followed by seven cardinals, by thirty-seven bishops and archbishops, and by the leading officials of the city led by the Gonfaloniere and the Priori. At the sound of the choir singing their hymn of praise many of the spectators were seen to be in tears.
After his father’s death Cosimo continued to pour Medici money into the building, restoration and embellishment of churches, convents and charitable institutions all over Florence and in the surrounding countryside, as though determined to leave his mark on Tuscany. ‘I know the humours of my city,’ he once remarked to his friend, Vespasiano da Bisticci. ‘Before fifty years have passed we shall be expelled, but my buildings will remain.’ First of all, as a member of a committee of four appointed by the Arte del Cambio, he had a share in commissioning Ghiberti to make a statue of St Matthew, patron of bankers, for one of the fourteen niches on the outside walls of Orsanmichele which had each been adopted by a guild.11 In paying for the work, Cosimo contributed more than his fellow bankers, as befitted his wealth, but only slightly more, in accordance with his accustomed discretion. After Orsanmichele, the novices’ dormitory and chapel at Santa Croce,12 the choir of Santissima Annunziata,13 the library of the now demolished church of San Bartolommeo, the monastery known as La Badia at San Domenico di Fiesole – where Cosimo had his own room14 – and San Girolamo nei Monti at Fiesole, all appear to have benefited from Cosimo’s munificence and from his undoubted knowledge of architectural matters, to which even the leading craftsmen and designers seem to have deferred. Cosimo was also responsible apparently for the restoration of a college for Florentine students in Paris, the renovation of the church of Santo Spirito in Jerusalem and for additions to the Franciscan monastery at Assisi. The year after the completion of the Cathedral dome he undoubtedly provided funds for Michelozzo to rebuild the monastery of San Marco; this was a charitable enterprise which, according to Vespasiano da Bisticci, Cosimo was induced to undertake by Pope Eugenius IV whom he had consulted at a time when his conscience troubled him. He eventually spent the enormous sum of 40,000 ducats on this Dominican monastery, whose exacting, ascetic and intimidating Prior, Antonio Pierozzi – known as Antonino because he was so small – became Archbishop of Florence in 1445, and in 1523 a saint. Antonino was one of Cosimo’s closest friends, and the two men could often be found talking together, and with other members of the community, in the large cell which Cosimo reserved for his own private use and to which he retreated by himself when feeling the need for quiet reflection. They often talked, so it was said, of usury and how that besetting sin of a banker’s life might be expiated. The Church’s ruling was that the usurer might obtain forgiveness only by restoring during his lifetime, or at his death, all that he had gained unrighteously; and cases were known of penitent bankers who had appalled their heirs by stipulating in their wills that the first charge upon their assets must be the payment of full restitution. The distribution of charity was an insufficient atonement; but practical churchmen were quick to suggest that it was a help; and no doubt Cosimo considered it to be so. Certainly he paid out enormous sums. According to his grandson, who came upon an account book covering the thirty-eight years 1434 to 1471,’ the incredible sum of 663,755 florins’ had been spent on ‘buildings, charities and taxes’. So generous was Cosimo towards San Marco, indeed, that the friars ‘in their modesty’ felt obliged to protest. But Cosimo passed over their complaints. ‘Never,’ he used to say, ‘shall I be able to give God enough to set him down in my books as a debtor.’ He subscribed money to endow the monastery when the restoration was completed, presented the friars with vestments, chalices and illustrated missals, as well as most of Niccolo Niccoli’s library, and employed numerous scribes to copy out codices to add to their collection.15
When the work on San Marco was finished, Cosimo decided to build a new palazzo for his own family. He had moved some years before from the Palazzo Bardi to his father’s house in the Piazza del Duomo which he had improved and extended; but while this old family house might have been large enough for his family’s personal needs, it was far too small for his business which urgently required new store-rooms and counting-houses. As the site for the new building he chose the corner of the Via Larga, the widest street in the city, and the Via de’ Gori which lay beneath the northern wall of the church of San Giovannino degli Scolopi.16 The architect he selected was the brilliant, cantankerous Filippo Brunelleschi whose work on the nave of the nearby church of San Lorenzo was now almost completed. But when he saw Brunelleschi’s plans and wooden model he thought them altogether too splendid and ornate, and rejected them as tactfully as he could. All the buildings which he had commissioned, and which he liked to consider as much his own works as those of the architects who had designed them, were quiet, restrained, composed and unemphatic and he wished his own palace to be the same. So, setting Brunelleschi’s plans aside, he turned instead to the younger architect, Michelozzo Michelozzi, a decision which so angered Brunelleschi that, in a bout of fury, he smashed his model ‘into a thousand pieces’.