Thanks to the mild climate, the protection of special greenhouses, special cultivation techniques, and devoted care, lemons, introduced in the late 13th century, could prosper also at this latitude. The production, also including cedars and oranges, reached its greatest expansion in the 18th century, with 18-20 million lemons per year. Considering the limited size of the cultivation area, it was a highly specialized and intensive cultivation, whose decline began in mid-19th century because of the gummosis, a plant illness given to a worse climate, and of the competition of the citrus fruits coming from the South.