Free Rome: An Empire's Story by Greg Woolf Page B

required provincials could earn it simply by intensifying the production of crops they already grew, since these were the crops Romans already knew and desired. Monocultures and cash crops never squeezed out pre-existing regimes in the Roman period. We know of no disastrous experiments with new crops. The empire expanded into regions that were already productive, and in most areas did no more than stimulate a modest intensification.
    The political unification of the Mediterranean has even been seen as simply the latest—political—phase in a much longer story, one that had begun with the spread of farming out from the Near East. It has been suggested that the limits of Roman expansion were set, in some regions at least, by the limits of this Old World agricultural complex. To be sure there was no ecological frontier dividing Roman from Persian spheres of influence, indeed that frontier cut through areas in north Syria that in every possible respect—cultural, religious, technological, and ecological—formed a unity. Yet Rome’s northern frontier at points reached areas where the returns from this style of agriculture do not seem to have been impressive during the Iron Age. Perhaps Roman conquest reached an ecological limit in northern Britain or the Low Countries. 13 Most of the long European frontier ran through rich agricultural land. Where Roman rule did meet real ecological limits was the Atlantic and the Sahara. The empire had successfully gained control of the southern part of that western corridor leading out of the Near East: threats came to it from north and east.
    Roman expansion followed agricultural change, and brought with it few new technologies, species, or diseases: consequently, Roman conquest had no cataclysmic ecological impact. But this does not mean that Romans were not positively interested in promoting intensification. One sign of Roman interest is the care they took to learn from the agricultural regimes they incorporated. The only book the Romans took from the libraries of Carthage after the sack of the city in 146 BC was Mago’s agricultural treatise which was then translated into Latin. Generals returning from the east brought back new species of plants, including cherry trees. Roman writers of the early empire were actually very well aware of how recently many nuts and fruit crops had been brought to Italy from the east. More than 40 per cent of the plants named in Columella’s first-century AD book On Agriculture were Greek in origin. The Natural History of his near contemporary Pliny the Elder describes in detail the various trees and other crops found in different parts of the empire, and their nutritional and sometimes medical benefits. Medical texts produce a wealth of information about cultivable species. Pliny was just as interested in the plants and animals of the western Mediterranean and even temperate Europe, but it is obvious from his account that the main direction of movement remained east to west.
    Roman entrepreneurs not only brought eastern crops to Italy, but also attempted to transplant various Mediterranean species north of the Alps. Apples, pears, cherries, plums, and walnuts were introduced to northernEurope very early on, as were celery, garlic, asparagus, cabbage, and carrots. Chestnut, probably used for wood rather than primarily as a food source, followed a little later. What these trees and vegetables had in common—and what separated them from cereals—is that they required cultivation in gardens or orchards. Arboriculture involved a range of new specialized skills, such as grafting. It also required much greater inputs of energy and time in return for greater calorific and financial returns per hectare. The northward progress of these crops—like that of the vine—reflects the spread of Mediterranean taste, as well as of agricultural knowledge. Carbonized remains of these crops appear on settlement sites alongside those of others that could not be domesticated