cornice that led Eneide Mignacca to conclude that the ovoid profile, seen now in the end product, was an essential part of Michelangelo's first (and last) concept. The sculptor/architect has, figuratively speaking, taken all the previous designs in hand and compressed their contours as if the building were a lump of clay. The dome must appear to thrust upwards because of the apparent pressure created by flattening the building's angles and restraining its projections. If this explanation is the correct one, then the profile of the dome is not merely a structural solution, as perceived by Giacomo della Porta; it is part of the integrated design solution that is about visual tension and compression. In one sense, Michelangelo's dome may appear to look backward to the Gothic profile of Florence Cathedral and ignore the Classicism of the Renaissance, but on the other hand, perhaps more than any other building of the 16th century, it prefigures the architecture of the Baroque. Completion Giacomo della Porta and Domenico Fontana brought the dome to completion in 1590, the last year of the reign of Sixtus V. His successor, Gregory XIV, saw Fontana complete the lantern and had an inscription to the honour of Sixtus V placed around its inner opening. The next pope, Clement VIII, had the cross raised into place, an event which took all day, and was accompanied by the ringing of the bells of all the city's churches. In the arms of the cross are set two lead caskets, one containing a fragment of the True Cross and a relic of St. Andrew and the other containing medallions of the Holy Lamb. In the mid-18th century, cracks appeared in the dome, so four iron chains were installed between the two shells to bind it, like the rings that keep a barrel from bursting. As many as ten chains have been installed at various times, the earliest possibly planned by Michelangelo himself as a precaution, as Brunelleschi did at Florence Cathedral. Around the inside of the dome is written, in letters high: Beneath the lantern is the inscription: Discovery of Michelangelo draft On 7 December 2007, a fragment of a red chalk drawing of a section of the dome of the basilica, almost certainly by the hand of Michelangelo, was discovered in the Vatican archives. The drawing shows a small precisely drafted section of the plan of the entablature above two