For instance, the study did not examine the orientation of Pompeii. This city's two main roads are not obvious since the Romans later modified the city's layout.
Among 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. He extracted this orientation from available archaeological maps or by using a precision magnetic compass on site.
"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," Magli said.
Basically, there are only three towns oriented toward the north: Pesaro, Rimini and Senigallia. These three towns also lie relatively close to the west coast of central Italy.
Only two towns in northern Italy — Verona and Vicenza — lie near the summer solstice sunrise line. Geographically close, they were founded in the same period.
All the other studied towns are 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," Magli said.
"It is interesting research," Manuela Incerti, of Ferrara University's architecture department, said about the study. "It certainly opens the way to more extensive studies."
