The Pantheon has the largest un-reinforced dome in the world and was the largest dome until the completion of the Duomo of Florence in 1436. Constructed of un-reinforced concrete it has a height of 43.3m which equals the dome's diameter. Two identical domes placed together would make a perfect sphere.
The Pantheon was built originally as a temple by Marcus Aggrippa, Consul of Rome and son-in-law of the Emperor Augustus around 25 BC and was dedicated to the Roman Gods (“Pan" means everything, "theon", divine). This is confirmed by the inscription above the entrance which states that "Marcus Agrippa, son of Lucius, in his third consulate, made it." This refers to the original temple and not the current one. Aggrippa’s temple was rectangular in shape and was destroyed by fire in the rein of Domitian, which was then to be rebuilt by him, although that too was destroyed by fire. The one that exists today was constructed by the Emperor Hadrian during the period 118 to 128 AD and the examination of the building indicates the level of the ground when it was first constructed.
The best preserved of all ancient Roman buildings, it owes its preservation to the fact that in 609 AD it was given to Pope Boniface IV who converted it to a church and dedicated it to the Virgin Mary placing the bones of Christian martyrs under the main altar. In 1624 the bronze was removed from the beams in the Pantheon for the construction of the baldacchino in St Peters Basilica. To compensate for the removal, Pope Urban VIII (1623-1644) added the two bell towers designed by Bernini which became known as "the donkey ears of Bernini;" these were demolished in 1883.
The main part of the building is circular with the entrance through a rectangular structure linking the portico with the rotunda. The portico has three ranks of large granite Corinthian columns (eight in the first rank and two groups of four behind). The capitals of the columns are all damaged, except for the three columns on the eastern side. These three columns were replaced in 1666 with columns taken from the Baths of Severus Alexander. The pediment was originally decorated with a sculpture and holes may still be seen for the clamps which held the sculpture. Within the walls at the back of the portico were niches, which probably held statues of Caesar, Augustus and Agrippa, or Jupiter, Juno and Minerva - known as the Capitoline Triad. The entrance doors to the Pantheon are 7m high (22 feet) and made out of bronze, these were once covered with gold.
Inside the Pantheon is a coffered, concrete dome; the concrete consisting of hydrate of lime, pozzolanic ash, pumice with small pieces of rock (around 100mm in diameter) which was constructed over a formwork, similar to the technology used today.
At the centre of the dome is the oculus, which measures over 8 metres (27 feet) across and the source of light in the building. Any rain that enters collects in a drain in the centre of the floor. On the 21st June (the summer equinox), the sun rays shine from the oculus through the front door.
Along the interior walls can be seen marble columns, niches with memorial portrait busts, the seven arched recesses originally housed statues of the seven ancient Gods. Today, the walls of the Pantheon have lost much of their splendour. Originally they were covered by Pentelian white marble and stucco, traces of these can still be seen.
Located inside the Pantheon are a number of tombs, these include the tombs of Vittorio (Victor) Emmanuel II, first king of a unified Italy; his successor, King Umberto I. Although Italy has been a "Republic" since 1946 members of the Italian monarchist organization holds a vigil over their tombs. Also buried within the Pantheon in 1520 is the Italian artist Raphael, he worked in some of the Papal apartments in the Vatican and his work typifies the classical phase of the Renaissance.
Above the altar is a 7th century icon of the Madonna and Child which dates from when the temple was first converted to a Christian church. Although rare today these were common in Roman churches at that time. The Pantheon remains a church to this day and is still used for the celebration of mass, marriages and on special occasions.
Front view of the Pantheon with the inscription carved in stone above the columns confirming that it was origionally made by Marcus Agripa
The side view provides a good view of the buildings shape and dome.
Interior of the building showing the coffered, concrete dome and circular shape of the building.
Interior of the building showing the coffered,
concrete dome and circular shape of the building.
To see more photographs and take a virtual tour of the site click on the photoshow below.