Middlesex and crossed the Thames, but the British prince Cassivellaunus
with his war-chariots harassed the Roman columns, and Caesar was compelled
to return to Gaul after imposing a tribute which was never paid.

The next two years witnessed the final struggle of the Gauls for freedom.
Just before the second crossing to Britain, Dumnorix, an Aeduan chief, had
been detected in treasonable intrigues, and killed in an attempt to escape
from Caesar's camp. At the close of the campaign Caesar distributed his
legions over a somewhat wide extent of territory. Two of their camps were
treacherously attacked. At Aduatuca (near Aix-la-Chapelle) a newly-raised
legion was cut to pieces by the Eburones under Ambiorix, while Quintus
Cicero was besieged in the neighbourhood of Namur and only just relieved in
time by Caesar, who was obliged to winter in Gaul in order to check the
spread of the rebellion. Indutiomarus, indeed, chief of the Treveri (about
Treves), revolted and attacked Labienus, but was defeated and killed. The
campaign of 53 B.C. was marked by a second crossing of the Rhine and by the
destruction of the Eburones, whose leader Ambiorix, however, escaped. In
the autumn Caesar held a conference at Durocortorum (Reims), and Acco, a
chief of the Senones, was convicted of treason and flogged to death.

Early in 52 B.C. some Roman traders were massacred at Cenabum (Orleans),
and, on hearing the news, the Arverni revolted under Vercingetorix and were
quickly joined by other tribes, especially the Bituriges, whose capital was
Avaricum (Bourges). Caesar hastened back from Italy, slipped past
Vercingetorix and reached Agedincum (Sens), the headquarters of his
legions. Vercingetorix saw that Caesar could not be met in open battle, and
determined to concentrate his forces in a few strong positions. Caesar
first besieged and took Avaricum, whose occupants were massacred, and then
invested Gergovia (near the Puy-de-Dome), the capital of the Arverni, but
suffered a severe repulse and was forced to raise the siege. Hearing that
the Roman province was threatened, he marched westward, defeated
Vercingetorix near Dijon and shut him up in Alesia (Mont-Auxois), which he
surrounded with lines of circumvallation. An attempt at relief by
Vercassivellaunus was defeated after a desperate struggle and Vercingetorix
surrendered. The struggle was over except for some isolated operations in
51 B.C., ending with the siege and capture of Uxellodunum (Pu