Introduction

Republican Italy is defined for the purposes of this chapter as peninsular Italy south of the Po valley (see Map 6). This is a self-contained geomorphological zone by most definitions.1 The very nature of the peninsula means that it projects into the Mediterranean Sea, creating a central strategic position within the Mediterranean. The eastern flank of the peninsula is covered by the Adriatic, whose access is potentially blocked by the control of the narrows from the Capo d’Otranto across to the Balkan peninsula. The western Tyrrhenian flank is more accessible. The straits of Messina, between Calabria and Sicily, form one point of control, but the whole Tyrrhenian seaboard can also be approached from the west. In these western approaches, the Bay of Naples and the delta of the Tiber form two important nodal zones of communication from the sea and into the hinterland through major rivers. The first was the most northerly point on the peninsula where Greeks placed their colonies. The second was the core area of indigenous state formation. In the area north of the Tiber, the Etruscans first developed the most powerful states of Italy in the central Mediterranean in the course of the early first millennium. In the area immediately south of the Tiber and beyond, the Latins replaced them by the time of the republican period as the leading force.

The climate of republican Italy was essentially the Mediterranean climate of today: a wet winter and an extremely dry summer; although some authors (e. g., Burroughs 2001) suggest that the climate may have been warmer and drier, which would have had implications both for agriculture and health (particularly malaria - see below). Sea level (in areas not subject to tectonic instability) was also relatively stable and has

Not altered more than half a meter in the last 2000 years, although particular local circumstances along the Tyrrhenian coast may have led to some apparent sea level rise.3 The altitudinal relief emphasized below was more important in determining variation in the nature ofrainfall, temperature, and vegetational cover. The changes in environment were highly regional, generally precipitated by human action working on the potential fragility of the Mediterranean landscape, especially at times of seasonally low vegetation cover between September and November, leading to erosion and alluviation.