Trouble With the Alemanni
Events in the empire were very quiet for a change. In Rome, the senate seemed to be silent in its opposition to Stilicho, his few remaining opponents unable to do anything due to his virtual unassailable position. The imperial capital was moved back to Milan for the time being, with Stilicho feeling comfortable in letting Honorius reside in the city, due there being no foreseeable threats to Italy.
Even Alaric, the self-proclaimed “King of the Goths”, who had caused so much trouble in the west, was silent. Stilicho had been right in his assumption that Alaric would be content with his former position. Of course, Stilicho’s recent revamping of his cavalry arm, and increased recruitment from Illyricum, must have played a role in keeping Alaric quiet.
Following Stilicho’s campaigns in 409 and his placement of freshly recruited Limitanei on the border along the Rhine, the frontier stabilized for the time being. He appointed a new comes to the province, a capable commander by the name of Constantius. A strong supporter of Stilicho, Constantius had proved himself under Stilicho to be a very able commander. It is important to note, that although Constantius was ambitious, he was also very loyal to Stilicho. It is likely Stilicho recognized this, and we cannot rule out the possibility that he saw in Constantius a potential successor to his position of magister militum.
In the summer of 412 however, the Alemanni once again crossed the Rhine into Gaul. They may have been encouraged by the false reports of Stilicho’s death, which had surfaced around the time and nearly caused a mutiny among his troops. It had only been his arrival before the troops, proving that the rumors were in fact false, that prevented the mutiny. They were numbered at some 25,000 men.
It is odd that they would have crossed in the summer, when the borders would have been most heavily guarded. The likely explanation is they would have wanted to capitalize on the perceived death of Stilicho, before the power vacuum could be filled and the situation stabilized. The defenders along the area seemed to have been defeated in a small scale battle outside Augusta Raurica. From there, the Romans retired to Aventicum, sending word out to Stilicho and Constantius of the invasion, before being besieged by the Alemanni forces.
Stilicho felt more urgency in dealing with this than he did in suring up the borders after the attempted invasion in 406 due to its proximity to the Alps and Italy. He quickly gathered up some of his men scattered throughout northern Italy, amassing a force of some 20,000 near Milan, strengthened by an increased cavalry wing, and almost entirely Roman. This was not his full force however, as he had to leave behind troops to guard the Julian Alps in case Alaric saw this as a ripe opportunity.
Meanwhile, when word reached Constantius, he immediately gathered the 13-15,000 man field army in Gaul, and began marching out from Lugdonum. Upon hearing of Stilicho preparing to march through the Alps, plans were made for a pincer movement to outmaneuver and surround the Alemanni forces.
Battle Of Vesontio
Battle of Vesontio
Constantius arrived with such speed on Aventicum, that he nearly caught the Alemanni by surprise. They managed to get wind of his approach just in time, and broke off their siege. A small engagement occurred, but the results were largely indecisive, and the Alemanni turned north towards Vesontio. Constantius shadowed them, as Stilicho crossed the Alps and, unbenounced to the Alemanni, began marching with all haste towards them.
Another engagement occurred, this time much more decisive. Constantius, by now knowing Stilicho was just behind, launched a surprise strike on the Alemanni. Caught slightly off guard, the Alemanni at first began to falter, but regained their bearings and began to use their superior numbers to turn the tide in their favor.
At the start of the battle however, Stilicho had only been no more than around an hour away. It was now, that his forces arrived on the scene, first the cavalry, followed by the infantry. The Alemanni cavalry was taken by surprise and routed from the field, leaving Stilicho and Constantius’ cavalry free reign to smash into the flanks and rear of the infantry. Struggling to figure out what had just hit them, chaos and confusion consumed the Alemanni ranks. At this point Stilicho’s infantry engaged, sending any resistance left into full fledged rout. Many were cut down, and the Alemanni kind, whom we don’t know his name, was slain.
As they approached the river, what was left of the Alemanni forces struggled to cross. Relentlessly hounded by the Roman forces, most were slaughtered or drowned in the river. The casualty results for the Alemanni in the end were over 20,000. For Constantius, the initial stage of the battle being where he incurred the most losses, he lost around 3,000 men. Stilicho’s forces seemed to have remained relatively unscathed, with no account putting his casualties more than 1,000. The result was a crushing blow to the Alemanni, and a decisive victory for Stilicho and Constantius. A treaty was established, with the Alemanni submitting (not in the sense that they became a part of the empire) and, ceasing to be a threat.