The Pantheon is one of the most recognisable Roman buildings in Rome’s city centre.
Construction of the Pantheon started in 27 BCE on the order of Marcus Agrippa. It is one of the few buildings from ancient Rome that has stayed completely intact.
The current temple and characteristic round dome were not built until the 2nd century, under emperor Hadrian, after Agrippa’s building was damaged by a large fire in 80 CE and again in 110 when it was struck by lightning.
The façade shows the following text in bronze, ‘M.AGRIPPA.L.F.COS.TERTIUM.FECIT’. It means, ‘Marcus Agrippa, son of Lucius, third-time consul, has built this’.
Interestingly, this text was added during the rule of emperor Hadrian.
It is remarkable that people still do not know what the Pantheon building’s original purpose was. The name Pantheon comes from Greek and means ‘devoted to all gods’. The Pantheon was not used as a church until 608, when emperor Phocas gave the building to pope Boniface IV. The church was named ‘Santa Maria ad Martyres’. Over time, more and more altars and grave monuments were added, such as the grave of various Italian kings and the famous painter Raphael. These tombs can be found in the seven niches surrounding the central space.
The dome of the Pantheon
The opening in the dome has a diameter of 8.7 metres and lets in light in a special way (as well as rain at times).
In addition to being a source of light, this ‘oculus’ was a deliberate addition to Hadrian’s design to let the visitors of the temple be in direct contact with the heavens.
The total dome has a diameter of 44.4 metres and is the largest unreinforced concrete dome in the world.
The diameter is noteworthy as it is the same as the height from the floor to the oculus.
At the edges, the dome is over seven metres thick, made of heavy types of rock.
Near the oculus, the thickness of the dome is only 1.2 metres, made mostly of light pumice.
Originally, the ceiling of the Pantheon was clad with bronze. However, that was melted down under pope Urban VIII and – according to rumour – used by Bernini to create the baldachin above Peter’s grave (in St. Peter’s Basilica).
This turned out to be untrue, as Bernini did not trust the alloy.