Pompéi (Italie): Star-aligned temples hint at Pompeii's religious mix
Victoria Jaggard
Pompeii's Temple of Apollo: possibly aligned with the star Phact. Vesuvuis can be seen in the background (Image: Rene Mattes/Hemis/Corbis)
Mount Vesuvius looms large in the story of Pompeii – but the temples of the ill-fated Roman town might have looked to loftier bodies. A preliminary survey of 11 temples in the ruins found evidence that at least nine were aligned with the rising of particular stars or with the position of the sun or moon on days of cultural significance.
If confirmed, the discovery could offer a unique perspective on the blending of religions in the heyday of the Roman Empire.
Pompeii had been a Greek and Phoenician port of call for hundreds of years before it fell under Roman rule in 80 BC. Buried under volcanic ash from Vesuvius's major eruption in AD 79, Pompeii's well-preserved ruins are famed for the insight they provide into Roman life.
Vance Tiede of research agency Astro-Archaeology Surveys in Guilford, Connecticut, is interested in the way that this insight sometimes contradicts known Roman texts. For instance, a Roman architectural principle states that sacred sites should face west, but not all of Pompeii's temples do so – perhaps because temples in coastal towns were built according to other religious principles.
Ancient sailors
"Back then you had lots of mixtures of cultures trading by sea, and lots of temples at harbour ports like Pompeii," says Tiede. "There are really only two things those ancient sailors liked to do when they landed: first they'd visit a house of ill repute and get something to eat, then they'd visit the temples to pray for fair winds. Then they're off again. So Pompeii is a microcosm of what's going on in the Mediterranean at that time." You can compare lots of religious traditions in temple architecture, all in one town, he says.
To see if heavenly objects played a role in temple orientation at Pompeii, Tiede combined digital elevation models, satellite images, ground surveys and maps of the past positions of stars. In work presented last week at a meeting of the American Astronomical Society in National Harbor, Maryland, he showed that most of the temples have potential links to celestial objects important in Greek, Roman and Egyptian mythology.
For instance, in Greek and Roman myth, the hunter Orion was killed by a scorpion. The constellations Orion and Scorpius both dip below the horizon and then reappear in the sky during opposing seasons and so seem to chase each other across the heavens. Tiede found that in Pompeii, the Temple of Jupiter is aligned to the first pre-dawn appearance of the star Sargas, the "stinger" of Scorpius, while the Doric Temple faces the first emergence of the star Rigel, which marks Orion's heel.
Oddly, two Greek temples in Pompeii – those for Apollo and Venus – appear to be aligned with a relatively obscure star called Phact, which has no known importance in Graeco-Roman myth. However, Tiede has uncovered previous work that shows alignments of Phact with at least 12 temples in Thebes for the Egyptian god Amun.
"Greek sailors had been visiting Egypt since the time of Alexander the Great and the founding of the city of Alexandria," says Tiede. "Afterwards you start to see a fusion, if you like, of Greek and Egyptian religions, including in temple architecture. So you could have Hellenistic temples borrowing architectural rules from colonies in Egypt."
Scattered stars
Nevertheless, it is too early to attribute any specific significance to these astronomical ties. "Although his approach is serious and technically correct, what he finds is a series of scattered alignments to different stars and moon positions," says Giulio Magli at the Polytechnic University of Milan, Italy. "It is easy to match stars with alignments in this way. The situation would be changed if the author could set up a data set of, say, 10 temples of Isis orientated towards the moon during Roman times."
Other historians say the idea of star alignments in Pompeii is plausible. "I have little doubt that the constellations were important in the siting and arrangement of cults and their rituals," says Steven Ellis at the University of Cincinnati in Ohio, who has done extensive archaeological work in Pompeii. And Claudia Moser at the Joukowsky Institute for Archaeology and the Ancient World in Rhode Island says that it is possible the builders of at least some pre-Roman temples in Pompeii were taking astronomical influences into account.
Tiede says that the next step is to look for astronomical alignments in other Roman towns, particularly those where cultures mingled, to see if they show similar evidence. If he is right, the famed lost city of Pompeii could give us fresh perspective on ancient Rome's cultural melting pot.
"This is not just about celestial mechanics and mathematics," says Tiede. "It's a way to track the cultural exchange of people by sea from point to point."
