When Michelangelo died in 1564, the walls were being built, the piers had been strengthened and everything was ready for the building of the dome. The Pope wanted Michelangelo's assistant Vignola to finish it, but he was not able to. After twenty years Pope Sixtus V gave the job to the architect Giacomo della Porta and the engineer Domenico Fontana. Giacomo Della Porta successfully built the dome. He made some changes to the design, like adding some lions' heads to the decoration because they were the symbol of Pope Sixtus' family. The main way that the dome is different from the wooden model is that it is much more pointy.
Some writers believe that Michelangelo had changed his mind from his first plan, and did not want the pointy dome. They believe he wanted a round dome which would look more "restful". Other writers believe that Michelangelo wanted the pointed dome, not just because it was safer to build, but also because it looked more exciting, as if the building was pushing upwards. Pope Sixtus V lived just long enough to see the dome finished in 1590. His name is written in gold letters around the inside, just below the lantern.
Pope Clement III, had a cross raised into place on top of the lantern. It took a whole day and everyone in Rome was given a holiday, and all the church-bells of the city were rung. In the arms of the cross are set two lead boxes, one containing a fragment of the True Cross and a bone of Saint Andrew and the other containing medals of the "Holy Lamb".
The dome of St. Peter's rises to a height of 136.57 m (448.06 ft) from the floor of the basilica. It is the tallest dome in the world. Its inside diameter is 41.47 metres (136.06 ft), just slightly smaller than those of the Pantheon and the Florence Cathedral.
Around the inside of the dome is written in letters 2 metres (6.5 ft) high:
In 1602 Pope Paul V put Carlo Maderna in charge of the building. On February 18 1606, workmen began to pull down the rest of the old basilica. Some people were very upset. The building committee felt guilty. They decided that the church was the wrong shape, and that they wanted a Latin Cross plan because it was the symbol of the death of Jesus. They wanted a "nave" which would cover all the Holy Ground where the old building had been. In 1607 Maderna's plans for the nave and the "facade" (the front) were accepted. For the inside, he used very large piers with pilasters like Michelangelo's, but he made a clear join between the two parts of the building. The building work began on May 7 1607 and 700 men were employed to do the work. In 1608, the facade was begun. In December 1614 the building was all finished except for the decorations on the ceiling. Early in 1615 the temporary wall between Michelangelo's building and the new nave was pulled down. All the mess was carted away, and the nave was ready for use by Palm Sunday.
The façade was designed by Maderna. It is 114.69 metres (376.28 ft) wide and 45.55 metres (149.44 ft) high and is built of pale grey travertine stone, with a giant Corinthian columns and a central triangular pediment. Along the roof-line are statues of Christ, John the Baptist, and eleven of the apostles.
Inside the main doors is a portico (a long hall) which runs across the front of the building and has five doors leading into the basilica. Its has a long curving roof decorated with gold. The light that comes through the doors shines on the beautifully patterned marble floor. At each end of the portico, set between columns, is a statue of a figure on horseback. They are Charlemagne sculpted by Cornacchini (18th century) to the south and Emperor Constantine by Bernini (1670) to the north. Maderna's last work at St. Peter's was to design a sunken crypt called the "Confessio" under the dome, where people can go to be nearer the burial place of the apostle. All around its marble handrail are 95 bronze lamps.
As a young boy Gianlorenzo Bernini (1598-1680) visited St. Peter's and said that one day he wanted to build "a mighty throne for the apostle". His wish came true. As a young man, in 1626, Pope Urban VIII asked him to work as architect for the basilica. Bernini spent the next fifty years thinking of new and beautiful things to design. He is thought of as the greatest architect and sculptor of the Baroque period.
Bernini's first work at St. Peter's was to design the "baldacchino" which is like a tent or "pavilion" above the High Altar. This amazing thing is 30 metres (98 ft) tall and is probably the largest piece of bronze in the world. It stands underneath the dome and has four huge bronze twisted columns decorated with olive leaves and bees, because bees were the symbol of Pope Urban. Pope Urban had a niece that he loved very much and he got Bernini to put her face and the face of her new-born baby boy on the columns as well.
Bernini had a great idea for Bramante's great big piers. He had four hollow "niches" carved into them where four huge statues could stand. The basilica owns some precious relics: a piece of the True Cross of Jesus, a veil that a woman wiped the face of Jesus with, while he was carrying the cross, the spear that was used to pierce Jesus side, and the bones of St. Andrew, the brother of St. Peter. No-one knows for sure whether these things are real or not, but for hundreds of years they have been precious. Bernini's plan was the make four marble statues of the four Holy people: St. Helena who found the cross, St. Longinus who was the soldier with the spear, St Veronica who wiped Jesus' face and St. Andrew. (See below)
Bernini's next job was to make a special throne out of bronze, to hold an ancient wood and ivory throne that had been at the basilica for more than 500 years. It is called the "Cattedra Petri" or "throne of St. Peter". The bronze throne, with the old wooden throne inside it, is held up high at the end of the basilica, by four important saints who are called "Doctors of the Church" because they were all great writers and teachers. The statues are made of bronze. They are Saints Ambrose and Augustine for the Church of Rome and Saints Athanasius and John Chrysostum for the Orthodox Church. Above the chair is a window which is made not from glass but thin translucent stone called alabaster. The Dove of the Holy Spirit is in the middle of the window with rays of light spreading out into the basilica through a sculpture of golden clouds and angels. Bernini designed this to look like a window into Heaven. There was a great celebration when the chair was put in place on January 16, 1666.
Bernini's last work for St. Peter's, 1676, was to decorate of the Chapel of the Sacrament. He designed a miniature version of Bramante's Tempietto, and made it in gilt bronze. On either side is an angel, one gazing in adoration and the other looking towards the viewer in welcome. Bernini died in 1680 in his 82nd year.
To the east of the basilica is the "Piazza di San Pietro" (St. Peter's Place). The piazza was designed by Bernini and built between 1656 and 1667. It was not an easy job because the designer had lots of things to think about. Firstly, many people complained that Maderna's "facade" on St. Peter's looked too wide, so Bernini wanted to make it look narrower, not wider. Secondly, in the old square left over from the Old St. Peter's, Pope Sixtus V had a monument set up. This monument was a precious Ancient Egyptian "obelisk" (which is like a tall column, but with four flat sides). From its base to the top of the cross (that the pope had put on top) it was 40 metres (131 ft) high, and had been brought to Rome in ancient times. The obelisk really should be at the center of the new square, but it was not in quite the right place, and was very difficult to move without breaking. The third problem was that Maderna had built a fountain to one side of the obelisk, and Bernini needed to make another fountain to match it, otherwise the design would look unbalanced.