When Caesar returned from his victorious campaigns in Gaul in the
first century B.C., Cicero exultantly exclaimed, "Now let the Alps
sink! the gods raised them to shelter Italy from the barbarians; they
are no longer needed." For nearly five centuries that continued true;
then the tribes of northern Europe could no longer be held back. When
the Roman emperors saw that the crisis had arrived, they recalled
their troops from Britain in 410 The rest of the Roman colonists soon
followed.
At this time we find this brief but expressive entry in the
"Anglo-Saxon Chronicle" (SS46, 99): "After this the Romans never ruled
in Britain." A few years later this entry occurs: "418. This year
the Romans collected all the treasures in Britain; some they hid in
the earth, so that no one since has been able to find them, and some
they carried with them into Gaul."