The PantheonRoman Mythology

The Pantheon — literally 'temple of all gods' — was dedicated to the principal deities of the Roman state. The original was built by Marcus Agrippa in 27-25 BCE (his name is still inscribed on the portico); the current building is Hadrian's complete reconstruction, completed around 126 CE.

The building's design is a cosmological statement. The dome represents the vault of heaven. The oculus — the 27-foot open hole at the dome's apex — represents the sun, the eye of Jupiter, the connection between the mortal world and the divine. When it rains, water falls through the oculus onto the slightly convex floor and drains through nearly invisible holes — a detail that has fascinated visitors for nearly two millennia.

The seven niches around the interior originally held statues of the seven planetary deities: Sol (Sun), Luna (Moon), Mercury, Venus, Mars, Jupiter, and Saturn — the same celestial bodies that gave their names to the days of the week. The building was a model of the Roman cosmos in stone and concrete.

The Pantheon stands in the heart of Rome, facing the Piazza della Rotonda with its Egyptian obelisk and Baroque fountain. The portico features 16 monolithic granite columns, each 39 feet tall and 5 feet in diameter, quarried in Egypt and transported across the Mediterranean.

The dome spans 142 feet — exactly equal to its height from floor to oculus — creating a perfect sphere inscribed within the cylinder of the walls. It remained the largest unreinforced concrete dome in the world for over 1,300 years and has never been surpassed. The concrete grows lighter toward the top, transitioning from heavy travertine at the base to light pumice near the oculus.

Hadrian's Pantheon was completed around 126 CE. It was converted to a Christian church (Santa Maria ad Martyres) in 609 CE by Pope Boniface IV — the conversion that saved it from the stone-robbing that destroyed most other Roman temples.

The dome's construction remains an active area of scholarly study. Researchers have proposed several methods — including stepped construction, temporary earth fill, and rotating formwork — though no single explanation is universally accepted. The concrete recipe, the stepped rings reducing the dome's thickness, and the coffering (which reduces weight without reducing strength) represent Roman engineering at its absolute peak. Michelangelo reportedly called it 'the design of angels, not of men.'