the owner and a tenant divide up a farm's produce; forced labour by slaves owned by aristocrats and supervised by slave managers; and other arrangements in which a farm was leased to a tenant. Cato the Elder (also known as "Cato the Censor") was a politician and statesman in the mid- to late Roman Republic and described his view of a farm of 100 iugera in the de agricultura. He claimed such a farm should have "a foreman, a foreman's wife, ten laborers, one ox driver, one donkey driver, one man in charge of the willow grove, one swineherd, in all sixteen persons; two oxen, two donkeys for wagon work, one donkey for the mill work." He also said that such a farm should have "three presses fully equipped, storage jars in which five vintages amounting to eight hundred cullei can be stored, twenty storage jars for wine-press refuse, twenty for grain, separate coverings for the jars, six fiber-covered half amphorae, four fiber-covered amphorae, two funnels, three basketwork strainers, [and] three strainers to dip up the flower, ten jars for [handling] the wine juice..." It is important to note that Cato's description is not indicative of the majority of farms in the early 2nd century BC. The de agricultura is a political document designed to show off Cato's character as much as it is a practical guide. Trade There was much commerce between the provinces of the empire, and all regions of the empire were largely economically interdependent. Some provinces specialized in the production of grains including wheat, emmer, spelt, barley, and millet; others in wine and others in olive oil, depending on the soil type. Columella writes in his De re rustica, "Soil that is heavy, chalky, and wet is not unsuited to the growing for winter wheat and spelt. Barley tolerates no place except one that is loose and dry." Pliny the Elder wrote extensively about agriculture in his Naturalis Historia from books XII to XIX, including chapter XVIII, The Natural History of Grain. Greek geographer Strabo considered the Po Valley (northern Italy) to be the most important economically because "all cereals do well, but the yield from millet is exceptional, because the soil is so well watered." The province of Etruria had heavy soil good for wheat. Volcanic soil in Campania made it well-suited for wine production. In addition to knowledge of different soil categories, the Romans