Pantheon

The first

Agrippa's date is on a building Hadrian finished

The first Pantheon was commissioned by Marcus Vipsanius Agrippa under Augustus. After it burnt down, the present building was completed by Hadrian and probably dedicated about AD 126, but Hadrian re-inscribed Agrippa's original date, so its exact date is uncertain.

The dome

Its concrete dome is still the world's largest

Almost two thousand years after it was built, the dome is still the world's largest unreinforced concrete dome. The height to the oculus and the diameter of the interior circle are the same, 43 metres, and the oculus is open to the sky.

43 mboth the interior diameter and the height to the oculus

The name

Nobody was sure what the name meant, even then

The name comes from a Greek word meaning of or common to all the gods. Cassius Dio, writing about 75 years after the rebuilding, was unsure of the reason, and suggested the statues of many gods or a dome that resembles the heavens.

A church

Becoming a church saved it from being stripped

In 609 the Byzantine emperor Phocas gave the building to Pope Boniface IV, who consecrated it as a church to St. Mary and the Martyrs on 13 May 609, and it has been a church ever since. That saved it from the abandonment and the worst of the stripping that most ancient Roman buildings suffered.

The bronze

A pope melted down the bronze trusses of the portico

In the 17th century Pope Urban VIII had the massive bronze trusses above the portico melted down. Carlo Fea found in the Pope's accounts that about 90% of the bronze went into cannon for Castel Sant'Angelo, and that the bronze for Bernini's baldachin came from Venice.