Built between 27 and 25 BC by Marco Vipsanio Agrippa who was the general of the roman navy and the son in law of Emperor Augustus. Due to fires, it was rebuilt by Domitian and later by Hadrian as it is today between 118-125 AD, recicling its original frontal inscription dedicated to Agrippa but reversing the entrance to North to let the sun in from South. The Temple, dedicated to all gods (from the greek pan theion literally all the divine), had inside the statues of the seven planetary divinities: Diana for the moon, Mars, Mercury, Jupiter, Venus, Saturn, Apollo for the sun. Surprisingly, it still has original 15 -meter-high columns of granite shipped from Egypt and original Mediterranean stones on the floor shaped as squares, representing the Earth, and circles representing the Sky. Its bronze door is arguably original and 7-meter high.
Its dome in concrete, the largest non-reinforced in the world, is a blend of mainly roman cement and pomice stone with a 9-meter-wide big eye (oculus) in the center bringing in sunlight to shine the room and rain wisely channeled into the sewer system by the 22 drainage holes on the floor. It is the tomb of Raphael, Annibale Carracci, Baldassarre Peruzzi, King Victor Emanuel II, King Umberto and Queen Margherita. Donated by the bizantine Emperor Phocas to Pope Bonifacius IV in the year 608 AD and turned into the church of St. Mary of the martyrs in 609 AD, it now hosts the statues of the Holy Family and celebrates masses on Sat pm and Sun am.
The most spectacular temple left from ancient Rome shows us after two thousand years its astronomical calculations, still surrounded by mystery. The sunlight, entering and projecting over the North side, used to show the dates of solstices and equinoxes. On early April and September, the Pantheon gives us an amazing show: at 1 pm (noon in ancient Rome due to solar time change) the sun enters from the oculus shining over the entrance arch with such a perfection that amazes every spectator inside.
In Ancient Rome, festivities dedicated to Cybele the Mother-Earth were held on April 4th-10th (Ludi Megalenses) whereas to Jupiter on September 5th-19th (Ludi Romani) and this light shows were probably connected to those celebrations.
The light of the sun within the days slowly moves down towards the gate and on April 21st, the legendary foundation date of Rome, it shines with its solar circle exactly over the entrance for the Emperor Hadrian, the Pontif Maximus (the highest priest), to enter.
These light shows were not uncommon in the ancient times and sites such as Abu Simbel, Stonehenge and Chichen Itzà confirm the importance given to the Sun by ancient populations.
The Emperor Hadrian in particolar was a keen traveller and was probably inspired by the Egyptian culture, its god-sun Amon-Ra and their obelisks that were considered petrified rays of light.
Below is the solar effect between 12.30 and 1 pm, registered on April 8th 2017.
