The south-western shoreline of Lake Garda is for the most part low and shelving, but at Manerba an outcrop of triassic limestone forms a dramatic, high promontory projecting into the lake (FIG. 1 ). This geological formation is stepped in two levels : the higher, inland part, called the ‘Rocca’, occupied during the Neolithic, Bronze Age, Iron Age and Roman periods, as well as being the site of a medieval castle (Borrello, 1973 ; Brogiolo, 1973), and the lower level, the Sasso, comprising a sheer cliff dropping some 90 m down to the lake edge, with, at its foot, a chalcolithic cemetery, as well as traces of both earlier and later use by man.

In a letter to Dr Mead in 1738, Francis Wise discussed the location of Alfred's famous battle-ground of Ashdown and described it as ‘containing large tracts of down and sheep pasture where the great Western road passes at this day, being called the Rudge or Ridgeway’ (Wise, 1738). Sir Richard Colt-Hoare rode along the Ridgeway in 1815 and wrote ‘these ridgeways were the roads made use of by the earliest inhabitants of Britain as lines of communication between their different towns and villages. They generally followed the highest ridges of land on which also we find their habitations: they were not paved with stone and gravel as in later times by the Romans but their basis was the firm and verdant turf’ (Colt-Hoare, 1819). His description is the first itinerary of the route now followed with delight by thousands. He passed Wayland's Smithy, and Uffington Castle, following then with a long and speculative account of the battle of Ashdown. He was not immune to the enjoyment of a view. ‘Hitherto the ridgeway had afforded no attraction with respect to country or view, its chief interest was from a recollection of the important historical events which had transpired on its borders, but on proceeding eastwards the eye was continually amused by an extensive prospect over a rich vale extending to Oxford on the left, with numerous church turrets peeping forth amidst the dense foliage with which the country is overspread. The scenery at the right exhibited an open and cultivated extent of land. A few barrows occurred occasionally alongside the trackway but I did not see any other marks of ancient population.’

Following the development of pollen analysis in the earlier part of this century, much effort was devoted to unravelling the sequence of vegetational change during and after the retreat of the last European ice-sheets. The outlines established, questions of causation came to the fore, and the debate focused on factors such as climatic change, rate of species migration from glacial refuges, and natural vegetational succession. In more recent decades, a further factor has been widely investigated, namely the possible influence of humans on the landscape, principally as farmers and smiths. The development and modification of hypotheses is well illustrated by the Elm Decline of the Atlantic period, where climate (Iversen, 1941) or man (Troels-Smith, 1960) and occasionally disease (see refs in Simmons & Tooley, 1981, 134) have been held responsible for a widespread but by no means straightforward decline in elm pollen.