The Valtellina measures 3,211 km2 with 183,000 inhabitants (2011 census) with a density of 57 inhabitants per km2.
It is one of the few alpine valleys east-west oriented, it is crossed entirely by the Adda river, from its birth (in Val Alpisella in the Stelvio National Park) until its entry into the lake of Como.
The valley has a glacial origin, its bottom is very small, in some areas it is at most a couple of Km, and then immediately begin the steep slopes. Steep slopes are more in the Rhaetian side and they are cultivated with Vineyards; on the orobic side the slopes are more easier and we can find chestnut trees until a height of 700-800 meters, then there are forests and alpine pastures.
Because of the steepness of these slopes it was necessary to create the terraces to make productive the same slopes.
Today there are still 2,500 miles in terraces walls (sometimes the walls are tall 5/6 meters) that are positioned along the sides of the mountains.
At one time they had to be much more (someone speaks about twice) if one includes the high terraces, located over the 800 mt; those places were cultivated by buckwheat to making polenta, sciatt, chiscioi and pizzoccheri and rye bread (typical brasciadeli-donuts).
Already in Roman times there was the Raethic wine. It's very probably that were the Tirreni (a population came from Estruscan pleople) that brought the screw in Valtellina.
The mjor expansion of vineyards occurred in the early Middle Ages, after the fall of the Roman Empire and the arrival in Valtellina of the Lombards before, and the last Carolingian Frankish after. The Carolingian allowed and encouraged the active role of religious orders, such as communities of Benedictines and Dominicans that constructed in the valley monasteries and Xenodochi. In thi area the most famous and still exist, albeit uninhabited ruins, are the two Xenodochi of Santa Perpetua and St. Romedio, in Tirano: the first it was built just above the village of Madonna di Tirano, the second one is nowadays in Helvetic territory but the ownership is of the town of Tirano. These two Xenodochi were located on the Via Valeriana (an ancient road built by the Romans) and they served as a refuge for travelers from North (Germany) down to the south (Rome) to visit the Pope.
To make the terraces was certainly not the clergy but they allowed to introduce a form of contract (called Accola) which consisted in giving in reliance to the farmers plots of land uncultivated a front of payments in foods or cash that consisted of a small salary that remained unchanged over the time. We can well say that in this period the formers were incentivated to cultivate the lands at the best. The Accole were also transmissible and salable too.
It was clear that with such favorable conditions, the farmer was spurred to convert all that it was possible to increase the profitability of the fund, because there were real benefits to ensure a decent quality of life to him and his family.
However the role of the monasteries was decisive until the beginning of 1300, then, over the years (due to the various political vicissitudes: domination of the French, then the domination of the Spanish, then again of the Ducato of Milan and finally in 1517 of the Swiss Tre Leghe) it began to decline and the large estates of the monasteries were replaced by private individuals.
The maximum expansion of the vineyards was in the nineteenth century, with over 6,000 hectares cultivated as vineyards.
About 2,000 hectares were planted with Chiavennasca (surely all terracing) while in the bottom of the valley were planted vines more productive and easy to grow.
Since the 50s of the twentieth century, most of the vineyards of the bottom of the valley were converted into the cultivation of apples (currently about 1,400 acres x 200 q.li/hectar, about 280,000 quintals of apples) and were absorbed by the urbanization of these areas.
Therefore we arrived to our days with 800 hectares of vineyards in the area DOP (former DOC and DOCG) which starts from Ardenno to arrive until Tirano (along 46 km) at an altitude ranging from 250 mt to 800 mt. almost all on the right side of the Adda river, at exception of the Stazzona area (Municipality of Villa di Tirano) and Albosaggia area (in front of Sondrio).