Ancient Romans built their towns based on astronomical grids

Ancient Romans built their towns using astronomically aligned grids, a recently concluded Italian study has revealed.

Washington, May 9 : Ancient Romans built their towns using astronomically aligned grids, a recently concluded Italian study has revealed.

As part of the study, researchers examined the orientation of some 38 towns in Italy, and found that all of them followed strong symbolic aspects linked to astronomy.

"It emerged that these towns were not laid out at random. On the contrary, they were planned following strong symbolic aspects, all linked to astronomy," said Giulio Magli of the mathematics department at Milan's Polytechnic University.

While ancient Roman writers, including Ovid and Plutarch, have documented how the foundation of a new town took into account the flight of birds and other astronomical references, "however, the link between Roman towns and sky symbolism has never been fully investigated," Magli said.

The Romans founded many towns, or colonies, especially during Rome's Republican period and the first Imperial period, roughly from the 5th century BC to the 1st century AD, and their layout inspired by the so-called castrum (a military camp), was nearly always the same.

The city consisted of a rectangle bounded by walls, with streets organized in a grid to form various residential quarters (insulae). Two main roads, called cardus and decumanus, criss-crossed the whole city, their intersection forming what would be termed in today's architectural parlance as the city centre. Four main gates placed at their ends completed the structure.

Magli however, did not examine the orientation of Pompeii, since the Romans later modified the city's layout in such a way that the city's two main became inconspicuous.

"I did not take into consideration all the Roman towns, but only those in which at least the two main roads are still clearly discernible," Magli said.

However, among the towns with two clear main roads, Magli looked at the orientation of grids' axes in relation to the movement of the rising sun at the eastern horizon over the course of the year.

Extraction of this orientation from available archaeological maps, or by using a precision magnetic compass on site, revealed that only three towns oriented toward the north: Pesaro, Rimini and Senigallia, all of which lay relatively close to the west coast of central Italy.

Two towns in northern Italy, Verona and Vicenza, lay near the summer solstice sunrise line. Geographically close, they were founded in the same period, the study further revealed.

"It emerged that the majority of Roman towns in Italy are aligned to sunrise, in relation to important sacred festivals or to the cardinal points," Discovery News quoted Magli as saying.

All the other towns studied were also found to be oriented either within 10 degrees southeast of sunrise, or near the winter solstice sunrise.

"Given these results, we can say that Roman towns in Italy are not randomly oriented. This will help us understand what kind of astronomical knowledge the Romans had," said Magli.

"It is interesting research. It certainly opens the way to more extensive studies," added Manuela Incerti, of Ferrara University's architecture department.

The study is part of a wider research published in Magli's book "Secrets of the Ancient Megalithic Towns," on the physics Web site, www.arXiv.org, maintained at Cornell University in Ithaca, New York.

ANI