Towards the end of Caesar's Gallic War, Rome had reached the Rhine.
Since the campaigns under Emperor Augustus (15 B.C.), larger troop
contingents were stationed along the river, with focal points around
*Mogontiacum/*Mainz and in northern Switzerland. After the Battle of the
Teutoburg Forest (9 AD), when the attempt to occupy all of Germania had
failed, the Lower Rhine remained the frontier of the empire's territory
until Late Antiquity. East of the Middle and Upper Rhine, however, the
Roman sphere of power was pushed forward several times over a period of
almost 200 years, and from 90 AD at the latest, the construction of
artificial borders was initiated. When the Roman expansion came to an
end around 160 AD, the province was secured in its furthest extension by
the "Frontal" or "Outer Upper-Germanic Limes", which existed until the
middle of the 3rd century. This book illustrates the historical and
archaeological significance of the Upper Germanic Limes and provides an
up-to-date overview of its manifold features in the field.