In prehistory the Rieti Valley was entirely occupied by a large lake which ancient Romans called Lake Velinus, since its tributary was the Velino river. The lake was formed during the quaternary, when limestone carried by water in the river deposited in the tight canyon where it flowed, shortly before joining the Nera river, near the present-day village of Marmore. As a result, the riverbed was occluded and the Rieti Plain was flooded becoming a lake. The water level in the lake rose and lowered several times during the centuries, favouring the formation of wide marshy zones around the lake where it was insalubrious to live because of malaria. For this reason in 271 BC, consul Manius Curius Dentatus decided to drain the lake by digging an artificial canal in the limestone rock at Marmore. This imposing engineering achievement created Cascata delle Marmore, a 165 m tall waterfall by means of which the Velino river could flow again into the Nera river, and allow the large and fertile valley to be farmed. Of the original great lake only some minor lakes remain, the largest being Lago di Piediluco. After the fall of the Roman Empire, lack of maintenance caused the canal to become obstructed again and in the Middle Ages the lake partially reformed. New draining interventions were ordered in 1545 by Pope Paul III; Antonio da Sangallo the Younger was charged to dig a new canal, but died of malaria in 1546 before the works were completed. Only in 1596 pope Clement VIII ordered new interventions, and Giovanni Fontana completed the new canal, ultimately draining the valley. Even if the lake disappeared, the recurring floods of the Velino river still caused trouble to farmers, disrupting their cultivations. This problem was solved in the Fascist era, when two large dams were built along the course of the two main tributaries of Velino to control their flow. As a result, the large artificial lakes Salto and Turano were formed.
Geography
The Rieti Plain has a semi-circular shape and extends by around 90 km², ranging from 370 to 380 metres above sea level; it is long 14 km and wide in average 7 km. It is bordered all round by mountains: Sabine Mountains at west and south, monti Reatini at east. Inside the plain two minor lakes can be found, residual of the ancient Lake Velinus: Lago Lungo and Lago di Ripasottile. This small wetland has preserved similar conditions to those present before the draining of the valley, and is a resting area to many migrating bird species; for this reason the area is now a nature reserve.
Agriculture
The Rieti Valley has always been known for its fertility, and it was sometimes nicknamed "the granary of Rome". Virgil wrote that, if a stick was planted in a field, it could not be seen anymore on the day after, due to the grass that had grown around it. In the 19th century wheat native to the Rieti Valley was famous all over Italy for being very productive and disease-resistant; agronomist Nazareno Strampelli used it as a starting point for his experiments, which led to the creation of wheat varieties that became popular all over the world in the mid-20th century. Other cultivations from the past were woad and sugar beet. Today the most important cultivations are corn, sunflowers and vegetables.
Tourism and pilgrimages
In the course of his life, saint Francis of Assisi visited repeatedly the Rieti Valley: the first time probably in 1209, then a long stay in 1223 and then another from the autumn of 1225 to April 1226. While in the valley, Francis represented for the first time the nativity scene, wrote the final version of the Franciscan Rule and probably also the Canticle of the Sun, but most importantly he founded the four shrines that are located at the four borders of the plain: Sanctuary of Greccio, La Foresta, Poggio Bustone and Fonte Colombo. The stay of Saint Francis coincided with a period in which Rieti enjoyed economic prosperity and became often a papal seat, from Innocent III in 1198 to Boniface VIII in 1298. Today franciscan sanctuaries have become objects of pilgrimages; tourists and pilgrims walk a path known as the Cammino di Francesco, which links the shrines and other landmarks such as Rieti's medioeval city centre, the Abbey of Saint Pastor and the Lungo and Ripasottile Lakes natural reserve.
