The Fall of the Western Roman Empire was the result of an inherent flaw in its grand strategy of military defence. The decision to prioritise the defence of Italia over that of the provinces effectively sapped the Empire of its economic and military strengths. The armies of Britain and particularly of Gaul, along with the grain of Africa, were the ultimate bases of strength for the Western Empire. Their defence was essential to the preservation of the Roman Empire in the West. In order to adequately defend the provinces, the Western capital and the strategic central reserve would need to be located outside of Italia.
The best military location from which to resist the barbarian assault, according to Arther Ferril’s The Fall of the Roman Empire, would have been Arles on the Rhone in southern Gaul. From the Rhone, it is quite possible that the barbarian invasion of Gaul, starting on the last day of the year 406, could have been prevented from penetrating Spain and southern Gaul. A more vigorous defence of the Rhine frontier would have prevented the rebellion of Constantine III in 407. To be sure, a government centred at Arles could not have prevented the invasion of Italia but the pressure on Constantinople to share in the defence of Italy would have been much greater.
Interestingly enough this relocation almost happened. In March 401 Alaric marched the Visigoths into Italy and up to the walls of Milan. The Visigothic leader had chosen an opportune moment for the invasion of the Po valley. Stilicho (the supreme commander of the West Roman legions at the time) was tied down in the Alpine province of Raetia to the north, dealing with an attack of Suevi, Alans and Vandals, so northern Italy was undefended against attack. Aquileia fell to Visigoths as well as other cities of northeastern Italy. Fear swept the Italian peninsula, and at Milan there was talk of moving the court to Arelate (Arles) on the Rhone. Repairs were hastily begun on the great walls of Rome while omens and prodigies foretold dire calamities.
In OTL Stilicho is able to persuade the court to hold out while he dealt first with the crisis on the Raetian frontiers and mobilised a field army for use against Alaric. So in the ATL he is unable to persuade the court (which has a strong anti-Stilicho faction anyway) and the Emperor and his extensive entourage move to the safer city of the Arles in 401. This unfortunately leaves northern Italy open to the ravages of the Goths).
Alaric abandons his plans to besiege Milan and marches south into central Italy where he threatens Rome herself. Stilicho assembles an army to meet the Visigoths, gathering legions from the Rhine and from Britain (weakening the borders of the Western Empire) as well as recruiting Alan and Vandal allies. Stilicho hopes to attack Alaric’s rear while he is still tied down to the siege of Rome but the barbarian leader refuses to be trapped by the approaching army and calls off the siege. Throughout 402, Alaric and Stilicho play cat and mouse throughout central and then northeastern Italy before a decisive is fought early in 403. Stilicho defeats the barbarian but is unable to destroy him and is in the end forced to make peace with the Visigoths, allowing Alaric to return to Illyricum (much like OTL but in the ATL Alaric is a little richer).
The 402 Gothic invasion of northern Italy reveals the weakness and impracticality of Milan as military base (just like in OTL). The court (based at Arles) debate moving the capital to another city in northern Italy (some favour the more impregnable and marshy Ravenna). But plans to return the capital back to Italia were muted after another Gothic horde (led by Radagaisus) pushed across the Danube and into Italy in 405.
Although Stilicho was once more able to marshal the dwindling armies of the Western Empire and defend Italy from the barbarians (massacring the Goths and bringing Radagaisus back to Rome in chains much like the OTL), the vulnerability of northern Italy was exposed. Despite some dissent, the court of Honorius decides to remain in Arles for the time being.
A new grand strategy was devised for the defensive of the West, the mobile army would remain in southeast Gaul (near the new imperial capital) while a smaller defensive force would stay behind in Italia. This defensive force would hold the invaders in a delaying action while the mobile army moved to the trouble spot. The whole plan was based on the resumption that northern Italy was not a defensible line against the new Gothic threat from the east (particularly Alaric in Illyricum).
In late 406, an alliance of Vandals, Suevi and Alans crosses the frozen Rhine and sweep through undefended northern Gaul. In OTL, Stilicho’s attention had turned towards the defence of Italy above all other pursuits (such as defending the frontiers) and he made no attempt to halt the invasion of Gaul. His inaction angered the legions in Britain, who appointed a usurper (Constantine) to the purple. Constantine crossed the channel to Gaul and became quickly gained control of over half the Western Roman Empire (ruling a large part of Gaul and Spain) for four years. In the same year Alaric marches west (again) from Illyricum towards Noricum, threatening northern Italy with invasion (again).
However in the ATL, Stilicho is committed to a new grand strategy that ranks the security of southern Gaul as integral. He is therefore forced to make provisions to defend Gaul. While he could just try and persuade Honorius to move the capital back to northern Italy, the threat from the Visigoths is at this moment too significant to makes this a viable proposal. So the Roman legionaries are summoned northward and Stilicho begins to gather an army to drive back the invaders.
A new chapter has begun in the history of the Western Roman Empire…
The best military location from which to resist the barbarian assault, according to Arther Ferril’s The Fall of the Roman Empire, would have been Arles on the Rhone in southern Gaul. From the Rhone, it is quite possible that the barbarian invasion of Gaul, starting on the last day of the year 406, could have been prevented from penetrating Spain and southern Gaul. A more vigorous defence of the Rhine frontier would have prevented the rebellion of Constantine III in 407. To be sure, a government centred at Arles could not have prevented the invasion of Italia but the pressure on Constantinople to share in the defence of Italy would have been much greater.
Interestingly enough this relocation almost happened. In March 401 Alaric marched the Visigoths into Italy and up to the walls of Milan. The Visigothic leader had chosen an opportune moment for the invasion of the Po valley. Stilicho (the supreme commander of the West Roman legions at the time) was tied down in the Alpine province of Raetia to the north, dealing with an attack of Suevi, Alans and Vandals, so northern Italy was undefended against attack. Aquileia fell to Visigoths as well as other cities of northeastern Italy. Fear swept the Italian peninsula, and at Milan there was talk of moving the court to Arelate (Arles) on the Rhone. Repairs were hastily begun on the great walls of Rome while omens and prodigies foretold dire calamities.
In OTL Stilicho is able to persuade the court to hold out while he dealt first with the crisis on the Raetian frontiers and mobilised a field army for use against Alaric. So in the ATL he is unable to persuade the court (which has a strong anti-Stilicho faction anyway) and the Emperor and his extensive entourage move to the safer city of the Arles in 401. This unfortunately leaves northern Italy open to the ravages of the Goths).
Alaric abandons his plans to besiege Milan and marches south into central Italy where he threatens Rome herself. Stilicho assembles an army to meet the Visigoths, gathering legions from the Rhine and from Britain (weakening the borders of the Western Empire) as well as recruiting Alan and Vandal allies. Stilicho hopes to attack Alaric’s rear while he is still tied down to the siege of Rome but the barbarian leader refuses to be trapped by the approaching army and calls off the siege. Throughout 402, Alaric and Stilicho play cat and mouse throughout central and then northeastern Italy before a decisive is fought early in 403. Stilicho defeats the barbarian but is unable to destroy him and is in the end forced to make peace with the Visigoths, allowing Alaric to return to Illyricum (much like OTL but in the ATL Alaric is a little richer).
The 402 Gothic invasion of northern Italy reveals the weakness and impracticality of Milan as military base (just like in OTL). The court (based at Arles) debate moving the capital to another city in northern Italy (some favour the more impregnable and marshy Ravenna). But plans to return the capital back to Italia were muted after another Gothic horde (led by Radagaisus) pushed across the Danube and into Italy in 405.
Although Stilicho was once more able to marshal the dwindling armies of the Western Empire and defend Italy from the barbarians (massacring the Goths and bringing Radagaisus back to Rome in chains much like the OTL), the vulnerability of northern Italy was exposed. Despite some dissent, the court of Honorius decides to remain in Arles for the time being.
A new grand strategy was devised for the defensive of the West, the mobile army would remain in southeast Gaul (near the new imperial capital) while a smaller defensive force would stay behind in Italia. This defensive force would hold the invaders in a delaying action while the mobile army moved to the trouble spot. The whole plan was based on the resumption that northern Italy was not a defensible line against the new Gothic threat from the east (particularly Alaric in Illyricum).
In late 406, an alliance of Vandals, Suevi and Alans crosses the frozen Rhine and sweep through undefended northern Gaul. In OTL, Stilicho’s attention had turned towards the defence of Italy above all other pursuits (such as defending the frontiers) and he made no attempt to halt the invasion of Gaul. His inaction angered the legions in Britain, who appointed a usurper (Constantine) to the purple. Constantine crossed the channel to Gaul and became quickly gained control of over half the Western Roman Empire (ruling a large part of Gaul and Spain) for four years. In the same year Alaric marches west (again) from Illyricum towards Noricum, threatening northern Italy with invasion (again).
However in the ATL, Stilicho is committed to a new grand strategy that ranks the security of southern Gaul as integral. He is therefore forced to make provisions to defend Gaul. While he could just try and persuade Honorius to move the capital back to northern Italy, the threat from the Visigoths is at this moment too significant to makes this a viable proposal. So the Roman legionaries are summoned northward and Stilicho begins to gather an army to drive back the invaders.
A new chapter has begun in the history of the Western Roman Empire…