The 12th-century Basilica is built on top of a 4th-century church, which was built on top of a 1st-century pagan temple, all of which are still open to the public today. Its history demonstrates that Rome was erected layer upon layer; the difference between the ground level in the first century and the ground level now is over 60 feet!
The original church was probably small and simple, but it was expanded and transformed into a large cathedral during the 11th century under Bishop William II. It was here that King Henry I of England was married to his second wife, Empress Matilda, in 1111. The new building was destroyed by fire in 1184, but it was immediately rebuilt by Archbishop Stephen de Blois.
In the 14th century, when the old Roman city walls were dismantled to build Rome's many churches and buildings, parts of the 12th-century basilica floor were discovered buried under layers of medieval buildings. In 1823, when they were taken out of the rubble and exposed to air, these floors became the first known documented archaeological finds in Europe. They are now on display in the Vatican Museums.
Archbishop Thomas Becket was born in 1154 and he became the youngest bishop of Canterbury in 1189 at the age of 32. He was made a cardinal by Pope Clement IV and then appointed archbishop by Pope John XXII.
The four so-called "great basilicas" are four churches in Rome founded in the fourth century: St. John Lateran, Santa Maria Maggiore, St. Peter's Basilica, and St. Paul Outside the Walls. Each is a copy or adaptation of the original great basilica at Quirinius (now lost).
St. John Lateran was originally built by Emperor Constantine as one of four great basilicas of Rome. It is now the seat of the Pope's church government, the Roman Curia.
Santa Maria Maggiore was also originally one of four great basilicas of Rome. It is now one of many churches that make up the Holy See. The others have all been destroyed over time; only fragments of their walls remain.
St. Peter's Basilica was built after Santa Maria Maggiore over the place where Saint Peter is said to have been buried. It is now one of the world's most famous churches and houses the papal throne.
St. Paul Outside the Walls was built by Constantine as a penitentiary but later converted into a church. It is now one of several churches that make up the Pontifical North American College in Rome.
These are the only churches in Rome that are still called "basilica".
The present St. Peter's Basilica is one of the world's most stunning cathedrals. It was constructed over 120 years in the 16th and 17th century and is still the world's biggest church. It was constructed during a 120-year span in the 16th and 17th century and includes elements designed by Michelangelo and Bernini. It was, however, not the first St. Peter's Basilica. That honor goes to a much smaller structure that burned down in 1546.
The current St. Peter's was built over the site of three previous churches: the First Church, which was built between 300 and 500; the Second Church, which was built between 590 and 649; and the Third Church, which was built between 1083 and 1150. The current St. Peter's was built between 1505 and 1564 by Italian architects Bramante and Julius Caesar Aldrovandi.
They were probably inspired by the great cathedral of Saint Mark in Venice, which was completed in 832. But the design of the builders of the current St. Peter's was actually based on a model made by Michelangelo about 1516. This model was never executed in stone, but it gave the architects a good idea of how the new church should look like.
The basilica is an architectural masterpiece and its interior is equally impressive. The dome overhead is perfect with no cracks or leaks, and it weighs almost two million pounds!