While in Rome I visited the Pantheon. I was really impressed by it. When you consider its size, age, and structure it truly is an engineering marvel. For starters I expected it to be out more in the open like the Colosseum for all the world to see, but instead it is sandwiched into a neighborhood.
As you are walking through the narrow streets of Rome and enter the Piazza della Rotunda, the Pantheon suddenly looms before your eyes … a huge monument of architectural triumph … having survived the test of time. It is likely the best preserved of all the buildings of ancient Rome.
It was oringinally built in 27 B.C. as a temple to all (pan) gods. It was damaged later by a couple of fires and was rebuilt by the emperor Hadrian circa A.D. 120 and is perhaps the most influential building in art history.
The ancient portico columns are an impressive 40 feet high and are made of single pieces of red-gray granite taken from an Egyptian temple. The holes in the triangular pediment once held a huge bronze Roman Eagle.
The porch ceiling was originally covered in bronze plating, but this was removed in the 17th century by the scavenging pope from the Barberini family.
The dome was the largest made until the Renaissance and is a testament to Roman engineering. It became a model for the Florence cathedral, Michelangelo’s dome of the St. Peter’s, and even Washington D.C.’s capitol building.
The dome is set on a circular base and is as high (142 feet from the floor tho the rooftop) as it is wide. It is made from concrete which was a Roman invention. It gets lighter and thinner as it reaches the top. The base is 23 feet thick and made from a heavier concrete mixed with travertine, but the top is less than five feet thick and is mixed with lighter volcanic rock. The indentions or ‘coffered’ ceiling reduces the weight of the dome without losing strength. The oculus, or eye-in-the-sky, is the only light source and measures nearly 30 feet across. The floor is 1800 years old. It has holes and slants toward the edges to let the rainwater drain off. (Notes taken from Rick Steve’s excellent travel book on Rome)
The Pantheon survived the Dark Ages primarily due to being transformed into a church. Centuries after Hadrian finished the rebuilding project the Roman Empire had been nearly completely evangelized and Emperor Phocas gave it to the church. Then in the year 609 Pope Boniface IV transformed it into the church of Sancta Maria ad Martyres. From that time on it has become a great reliquary, because the Pope wished it to be the final resting-place of the mortal remains of thousands of Christians, many of them martyrs, which until then had been buried in the Catacombs.
It was almost at the dawn of the Middle Ages that the dedication of the former Pantheon to the Christian Martyrs showed how deeply indebted the Church felt to those who had borne witness to Christ to the extreme of giving their lives for their faith. Tarcisius, Agnes, Cecillia, Perpetua, and Polycarp are examples of Christian faith in Christ being stronger than all the legions of Rome. “They had triumphed, like their Master, in the madness of the Cross, and so merited to be hymned and venerated down the centuries.” (Notes from Opus Dei)