The Diana: The Legend of Siena's Underground River
In a city like Siena, cradled by rolling hills and countryside but far from the sea, a steady water supply was a distant dream—so distant that only a river could have fulfilled it. Nevertheless, hope dripped right beneath the feet of the Sienese, who in the Middle Ages hypothesized the existence of a river to explain the presence of significant underground aquifers.
From the 4th century AD onward, Siena undertook a massive excavation of channels known as "bottini," which formed a veritable medieval aqueduct, replaced only recently by a modern one. Legend has it that when the workers paused to rest during the excavations, in absolute silence and darkness, they could hear a sound of hope: a massive river flowing placidly and undisturbed beneath the turmoil of life in a medieval city. It was a time when Siena was entering an era of flourishing trade and great changes, thanks in part to its location along the Via Francigena.
The physical and financial efforts to find this waterway, christened "The Diana" by the people, were so immense that all of Tuscany came to know the tenacity of the Sienese—though not without mocking them for the lack of results. Even the "Supreme Poet," Dante Alighieri—a rival from Florence—did not hesitate to borrow the legend to create a metaphor, mocking his neighbors as "vain folk" (gente vana) and making the myth famous throughout the peninsula.
History turned into legend, and between the 13th and 15th centuries, the Republic of Siena itself launched a new season of excavations to finally unveil the mystery and grant the people their dream of water. According to the stories, the river entered through Porta Ovile and exited through Porta San Marco, crossing the city from Northeast to Southwest.
Ultimately, despite the enormous investments, the Diana was never found. Yet, as in the best of fairy tales, the search was by no means in vain: the kilometers of tunnels carved beneath the pietra serena created a city beneath the city, testifying to the curiosity and strength of the Sienese through the centuries to the present day.
Today, following the tracks of the Diana is much simpler: you can visit the bottini themselves, admire Siena’s countless fountains—including the magnificent Fonte Gaia—or walk along "Via della Diana," which follows the legendary course of the river backwards from Porta San Marco to the heart of the city.
