Flavius Claudius Constantinus known as Constantine III (1). The last of a series of British supported usurpers
to the imperial throne of the Western Roman Empire.
At the end of 406 AD an army of assorted Germanic
tribes moved across the
frozen Rhine, defeated a force of Franks and moved
into Gaul; it was feared that
they would cross to Britain.
The Roman Army in Britain revolted, and following
the pattern set by Magnus
Maximus selected a series of usurpers as imperial candidates.
First Marcus, then Gratius were chosen, and when
found wanting by their
masters, discarded. Their choice then fell on one
Constantine; his origins are
obscure, Edward Gibbon says that he was only a "private
soldier". Nevertheless, in 407 AD
the Army proclaimed him imperator and he immediately
led an invasion force across
to the continent. The legions based in Gaul switched their allegiance
to him and Constantine seems to have reached some sort of agreement with
the invading tribes. Sufficient to enable him to claim Gaul as his own by 408 AD, when he
occupied Arles. (Which
had by now replaced Trier as the headquarters of the
Gallic prefecture.)
At which point it should be noted that whatever the
extent of the troop
withdrawals previously effected by Magnus Maximus and Stilicho,
that the army in Britain still
felt sufficiently confident in its own strength to
take on both the
barbarian invaders and the forces of Honorius, the
legitimate Emperor of the
Western Roman Empire.
With Gaul under control Constantine sent Gerontius
to invade Iberia and put down
an uprising by some of Honorius’ Iberian relatives.
Like Magnus Maximus before
him, Constantine now ruled a northern-western Empire
that stretched from Iberia to
Britain. (A task, it must be said that had been made somewhat easier by
the murder of Stilicho in
408 AD, which removed the ablest military commander in
the west.) Honorius was forced to recognise Constantine's authority, and shared the consulship with him in 409 AD .
But later that year Constantine's empire began to unravel. First
Britain, then much of northern
Gaul revolted, and when Constantine sought to replace
Gerontius with his son
Constans, Gerontius revolted in turn and acclaimed one
Maximus as emperor, and
moved his forces into Gaul and laid siege to
Arles.
Honorius response was to gather an army under the
command of one Constantius (2), who
advanced into Gaul in 411 AD, defeated Gerontius, and
besieged Constantine in
Arles. Constantine lost hope, took refuge in a church
and was ordained, perhaps thinking that this would save him.
It did not, he was soon captured and beheaded.
(1) History seems to refer to him as Constantine III despite his status as an usurper,
but he should not be
confused with the other Constantine III, who was
briefly emperor of the Eastern
Roman Empire in 641 AD or even the Constantine III who
was King of Scotland in
995-997 AD.)
(2) this would be the Constantius who later become the emperor
Constantius III in AD 421.
Part of the Sub-Roman Britain project, where sources are detailed.