The original Pantheon in Rome was a temple dedicated to all the major gods. The Pantheon later became the sanctuary of the kings of Italy. The structure of the Pantheon was rebuilt from the original rectangular temple built by Marcus Vipsanius Agrippa, son-in-law of Augustus, the first Roman emperor; maker's stamps in the bricks place this restoration between 118 and 125 AD: the inscription on the architrave attributes the construction to Agrippa during his third consulship:
M. Agrippa L.f. cos tertium fecit ("Marcus Agrippa, son of Lucius, built this when he was consul for the third time").
In the centre of the ceiling of the Pantheon is the oculus (Latin for "eye"), a 27 foot hole which allows light to fill the building and incidentally helps to support the ceiling. Also the concrete step rings around the base of the dome are heavy enough to resist the outward force of the dome and have kept the dome stable and relatively free from cracks.
The Roman gods and goddesses were a blend of several religious influences, many of them introduced via the Greek colonies of southern Italy.
- The Rotunda of the University of Virginia, in the United States was designed by Thomas Jefferson to represent the "authority of nature and power of reason". The design was inspired by the Roman Pantheon.
- Panthéon, Paris.
- 608 AD - Emperor Phocas (emperor over the Roman Empire of the East with power over Rome) donated the Pantheon to Pope Boniface IV.
- 13 May 609 AD - The Pantheon consecrated and dedicated to Our Lady and all the martyrs Sancta Maria ad Martyres.
- 663 AD - Emperor Constantinus III (of the Roman Empire of the East) removed the gold plated bronze brickwork together with a hoard of Roman treasures to take it to Constantinople (Istanbul).
- 5 April 1536 - Entry of Emperor Charles V into Rome. During his visit the Holy Romam Emperor ascended the roof of the Pantheon accompanied by, among others, one of the Crescenzi family. Upon his return home, however, he confessed to his father, that he felt inclined to have thrown the emperor down upon the pavement, to revenge the sack of his native city just nine years before. "My son," replied the father, "such things should be done, not talked of."
- 1632 - Pope Urban VIII (Maffeo Barberini) added the inscription to the back of the porch: "The Pantheon, the most celebrated edifice in the whole world." Urban VIII had the bronze ceiling from the portico melted down. Although there is some question as to what the bronze was used for it is thought that much of it went to build the canons in the Castel Sant'Angelo. The lampoon Quello che non fecero i barbari fu fatto dai Barberini" "what the barbarians did not do, the Barberini did" follows on from this act (the Barberini were a powerful family, with branches in Rome and Florence, which had produced several cardinals up to that point).