Alfalfa seems to have originated in south-central Asia, and was first cultivated in ancient Iran. According to Pliny (died 79 AD), it was introduced to Greece in about 490 BC when the Persians invaded Greek territory. Alfalfa cultivation is discussed in the fourth-century AD book "Opus Agriculturae" by Palladius, stating: "One sow-down lasts ten years. The crop may be cut four or six times a year ... A jugerum of it is abundantly sufficient for three horses all the year ... It may be given to cattle, but new provender is at first to be administered very sparingly, because it bloats up the cattle." Pliny and Palladius called alfalfa in Latin "medica", a name that referred to the Medes, a people who lived in ancient Iran. The ancient Greeks and Romans believed, probably correctly, that alfalfa came from the Medes' land, in today's Iran. (The ancient Greeks and Romans also used the name "medica" to mean a citron fruit, once again because it was believed to have come from the Medes' land). This name is the root of the modern scientific name for the alfalfa genus, "Medicago".