Built during the 1st century AD, with no exact date documented, by an unknown architect during the reign of Hadrian, it is known to be the second dome built in the world and the present structure is thought to have been originally built as a temple for all the pagan gods.
The rotonda is also believed to have been a Roman bath.
The portico which fronts the building is what remains of the original temple of Agrippa.
The Pantheon was built to emphasize the dome inside rather than outside, although the original bronze guilded roof tilesonce found on the dome but later, claimed by a Byzantine emperor on a short visit to Rome, might have made it more evident.
The Pantheon was made a Catholic Church after Rome's conversion to Catholicism. A masterpiece of both engineering and art, the Pantheon is most likely the best preserved of all Rome's ancient buildings.and a lasting memory of ancient Roman power. Church services are still held within it today.