Free Rome: An Empire's Story by Greg Woolf

end of the second millennium BC , humans were using one or another variation of this complex of cultigens and domesticates across Europe and the Mediterranean. Geese had been domesticated in ancient Egypt. Chickens, descended from jungle fowl in the Far East, appeared sometime in the middle of the last millennium. (There are no chickens in the Iliad , but Socrates’ last words were that he owed a cockerel to the god Asclepius.) Camels, domesticated much earlier in the Arabian peninsula, also moved progressively further west during the last millennium BC . Rabbits wereconfined to the Iberian peninsula until the turn of the millennium. Small animals might seem insignificant, but they were valuable as they might be bred fast and fed cheaply. In a world without refrigerators, small animals also posed fewer meat storage problems.
    The main technological innovations in agriculture also preceded Rome. Most important was metallurgy, also invented in the east. Gold was easiest to extract, but was nearly useless for making tools. Copper and then bronze working began in the Near East in the middle of the fourth millennium BC . What really made the difference to agriculture was the appearance of abundant iron tools, cheaper to produce and harder wearing than other metals. Ironworking was almost certainly discovered in north-west Anatolia towards the end of the second millennium BC : from there it spread throughout the Old World, reaching the Yangtzee, southern India, and Scandinavia by the middle of the last millennium BC . Iron agricultural tools were especially important in northern Europe where they made forest clearance and the cultivation of heavy soils much easier. The growth in the availability of iron tools in the middle of the last millennium BC runs parallel with agricultural and demographic expansion in the European interior. Evidence is provided not only by the great size of late Iron Age hillforts and other settlements, but also by the huge armies that began raiding and invading the Mediterranean world from the fourth century BC . Greeks and Roman were terrified by these invasions, but had no real notion of their causes.
    The temperate Europe that Julius Caesar and his successors found when they began serious warfare north of the Alps was already tamed. There were no longer any hunter-gatherer populations. Not was there any primeval forest. Forests had expanded in the early Holocene, following the retreat of the glaciers, but they had mostly been felled by the first farmers. The woodlands that replaced them were created and managed by human activity. Roman poets wrote of northern Europe as utterly savage, a continent of dense forests full of wild beasts. But Roman generals, and the tax collectors that followed in the early empire, will have appreciated the phenomenal agricultural productivity of European landscapes compared to the arid Mediterranean. Forests and game certainly survived, as they do today, but only on the higher ground between cultivated landscapes. Around the Mediterranean there was already the present-day landscape of garrigues , a characteristic type of shrubland rather like chapparal formed of plants that can tolerate the summer heat, alternating with small cleared plains on which cereals might be grown.
    Prehistoric agriculture was not limited to the production of grains: woodlands and wetlands were also exploited; salt, vital for preserving meat and fish, was mined, gathered from coastal salt pans, and traded; large herds of livestock were raised, and short-range transhumance was already practised. The range of animal and plant species cultivated by prehistoric societies might seem relatively small, but the impact of farming on the early Holocene fauna was already phenomenal. The top predators who had expanded out of ice age refugia into Europe now diminished in number as their prey and habitats were removed. Lions disappeared from Europe and eventually western Asia, while populations of wolves and bears