In late 401, Alaric, king of the Visigoths (Western Goths) invaded Italy. This was the first major barbarian invasion of Rome. Legions were summoned from all over the empire and the invasion was defeated, but more were to follow. Four years later, Radagaisus led his tribe of Goths across the Danube and invaded Italy. That winter, a huge army of migrating Vandals, Ostrogoths (Eastern Goths) and Alans crossed the Rhine and poured into Gaul. Nearly all the legions in the East were withdrawn and sent west to face the barbarian threat. Although some were defeated and forced to work as Roman soldiers, the invasions just kept coming. To make matters worse, in 407, Constantine III proclaimed himself emperor and revolted in Britain. He then invaded Gaul, leaving his son Constans to hold Britain. Alaric launched another invasion in 408, and was defeated just outside Rome.
That year, Arcadius died and his brother Honorius succeeded him. Alaric then invaded Italy for a third time. The western half of the empire seemed on the brink of collapse.
The crisis was averted by bribing the Visigoths with thousands of pounds of gold and land in Aquitaine (in Southwest Gaul). Meanwhile, the revolt of Constantine continued. He lost Hispania to another usurper, Maximus, who besieged Constantine's capital, Arles. However, a very able commander named Stilicho defeated Constantine and Maximus in 410. Honorius decided that Britain was to hard to control and abandoned it, telling the cities there to guard themselves. Very soon, several groups of Angles, Saxons and Jutes invaded England. As soon as Stilicho's men had returned to Constantinople, Jovinus revolted in Gaul, with support from Alans and Burgundians. He tried to negotiate with the Visigoths under Ataulf, but when Jovinus named his brother Sebastianus co-emperor, he decided to ally himself with Honorius. Ataulf defeated Jovinus from his base in Aquitaine. Honorius then invaded Aquitaine in 413 and reduced Ataulf's land to a small section in the far Southwest.
There were other Germanic tribes to think about though. The Franks invaded Northeast Gaul and the tribes that had invaded in 405 were still a problem, especially the Burgundians, who pushed into Southeast Gaul. For the next 10 years, Honorius ruled over a slowly deteriorating empire. When he finally died of edema in 423, a large portion of Gaul had been lost to Germanic tribes. The next emperor was Arcadius' son Theodosius II. Theodosius founded the university of Constantinople and tried to establish a system of law involving all the laws created in the past century. The Danube frontier was restructured and victories were won over the Visigoths and Franks in Gaul. However, a significant blow came in 426 when the Vandals invaded Hispania. Bonifacius, the Magister Militum for Africa, tried to gain power by inviting the Vandals into North Africa, but him and the Vandals were crushed in 431. However, Theodosius was forced to acknowledge the loss of most of Hispania to the Vandals and also the Suevi, who had failed to establish a foothold in Gaul and decided to start a kingdom in North Hispania. The final fall of New Carthage was in 435. A reconquest was organised but defeated easily by the Vandals. However, they were prevented from spreading into North Africa.
Meanwhile, Theodosius published his law code, the Codex Theodosianus, in 436. The weakened state of the empire meant that both the Persians and the Huns under Atilla declared war on Rome. The Persians never got very far, but the Huns continued raiding the Balkans for years. By 448, the Balkans were ravaged. That year, Theodosius died fighting against the Huns at the devastating Battle of Trimontium. Then, having defeated the Romans in the Balkans, and realising that he would still never capture Constantinople (the capital), Atilla turned on Gaul.
The next emperor was Marcian. He was pleased that Atilla had left the area around Constantinople, but realised that Atilla had a better chance in Gaul due to the pressure that was already on Gaul from the Germanic invasions. To defeat the Huns, Rome formed a coalition with several Germanic tribes.
The Huns were defeated, but not before most of Western Gaul had been destroyed. Atilla
then decided to invade Italy. This would have been disastrous for Italy if Atilla had not been killed in battle. A power struggle between his sons greatly weakened the Hunnish Empire, and it collapsed in 451.
Throughout this time, Persia attacked Rome. However, the attacks were held off. Also, the expansive Vandals led raids on North Africa, once nearly occupying Morocco. In 458, Marcian died of a disease, and Leo I was placed on the throne. It was thought by Aspar, an Alan who dominated the politics, that he would be an easy puppet ruler. However, he quickly asserted his own control and laid plans to retake some of the land that had been lost to barbarians. He gathered an army and marched west.
The first tribe he wanted to deal with were the Visigoths, who threatened to take control of the last Roman outposts in Gaul. They were defeated and their kingdom reduced to a small reigion of Aquitaine. Next were the Burgundians. They were also trying to gain land in Gaul. Leo managed to reclaim some land. Then the Suevi, who had occupied Northern Hispania. This time Leo was less successful. He was forced to admit defeat - his soldiers were weary and tired of battle. However, in 461 he tried another invasion of Hispania, this time from the South. The Vandals who occupied the region were posing a threat to the African provinces. A significant amount of land was recaptured, but when the army went away again, the Vandals quickly recaptured most of it.
A few years later, an usurper named Majorian gained power in Gaul, and allied himself with the Burgundians and the Visigoths. Meanwhile, the Ostrogoths invaded Illyria and the Balkans. Majorian was eventually overthrown in 465 by a joint Roman-Frankish force, however Childeric I of the Salian Franks forced Leo to give Northern Gaul to him.
In 469, the Vandals under Genseric led a massive army over the Strait of Gibraltar to Africa. They overwhelmed Morocco, and nearly succeeded in capturing Carthage, but nearly all the Roman legions were summoned and war went on, backwards and forwards through Africa until the Vandals were eventually forced to flee in 474. Unfortunately for the Vandals, the Suevi had taken a large part of their land in Hispania and they were reduced to only a small kingdom. Genseric died in the conflict and was succeeded by his son Huneric.
The Visigoths and Ostrogoths took advantage of this war by invading Southern Gaul and Italy in 473. This was the last, and most devastating, Barbarian invasion. This time the generals really struggled to prevent the tribes from capturing Italy. Ricimer was the main commander in the army at that time. When the Visigoths launched an assault on the remaning Roman territories in Gaul, he was quickly summoned there because by then the Vandals were nearly defeated. The Visigoths were winning the war, but not by much at that stage. Then the Ostrogoths invaded from Pannonia (OTL Hungary). Ricimer sent some of his soldiers to Northeast Italia, but they were quickly defeated and the Ostrogoth army poured into Italia. Meanwhile, the Visigoths renewed the attack and quickly captured Marseilles. In 474, the two armies met at Mediolanum and Theodoric of the Visigoths and Theodoric of the Ostrogoths discussed their battle plans. On Midsummer's day, the combined army of Goths swept South into Italia.
Ricimer was now cut off from the rest of the empire (apart from by sea). He decided to collect his troops and attack the Gothic army with as much force as possible, instead of waiting for them to attack Roman cities. He sent a message to the army in North Africa telling them to attack the Goths from the North. He then marched North to meet the Goths. At the battle of Aretium, Ricimer met the Gothic army which was nearly five times bigger than his. His troops fought well, but there were too many barbarians, and eventually Ricimer was killed. The Goths marched on southwards towards Rome.
Meanwhile, another group of soldiers under the control of Syagrius had defeated the Vandals and were sailing North to deal with the Goths. They landed at Marseilles and defeated the Visigoths there quickly. They then marched into Italia and surprised the Goths at Falerii who had expected any attack to come after they had secured control of the peninsula. They had only a short warning and had lost many me
n at the battle of Aretium. King Theodoric of the Visigoths was killed and eventually the Romans won the battle. Theodoric of the Ostrogoths fled back to Pannonia with the remains of his army.
This is regarded as the time of the end of the Roman Empire and the start of the Byzantine Empire, which was based on Greece rather than Italy. Italy was under threat from the Germanic tribes and the capital was in Constantinople. The main language switched from Latin to Greek.
Later that year, Leo died and his son in law, Zeno, became Emperor. As a result of the Battle of Falerii, the territory of the Visigoths passed to the Romans. The Ostrogoths survived.
In 478, a revolt began based on the idea that Zeno was a barbarian. It was led by Marcian, grandson of the earlier Emperor Marcian. He was helped by Scribonius and Illus. Zeno was quickly defeated at first, but when he bribed the Ostrogoths into helping him, things equalised. However, Marcian had the upper hand and was crowned Emperor. Within a year, he died however and Zeno defeated Scribonius and retook the throne. Illus kept up the fight for a while but was never much trouble to Zeno on his own.
In 481, Clovis became King of the Salian Franks. He began on a campaign to expand his territory. He fought many great battles against the other German tribes.
Meanwhile, Zeno was faced with trouble from the Ostrogoths. They had fully recovered from their failed invasion of Italy, and after being forced to help Zeno against Marcian, they decided that they had enough strength to rebel against the Byzantines. They were wrong. They were quickly defeated. They then decided to expand to the North, attacking tribes like the Gepids and Lombards.
The next decade was mainly peaceful. The Byzantines rebuilt up their strength after the Barbarians and Zeno issued his Thriskeftiki martyria (religious testament) in 482. When Zeno finally died in 492, the Empire was much stronger than it was before. He was succeeded by a powerful man called Anastasius. The first part of his reign was also peaceful. Economic prosperity was enjoyed. Anastasius also revived the coinage system, with the solidus in gold and the follis and nummus in bronze.
The seemingly undefeatable Visigoths rose again in 494 and rebelled against the empire. They secured control of Aquitaine and fought both the Empire and the Franks. They formed an alliance with the Suevi, and tried to attack Roman bases near Massilia (Marseilles). The Romans held them off, but Anastasius was not keen for war. In 497 he invited some of the Ostrogoths to destroy them. Theodoric refused to send his main force, but a fairly large group came. They, together with a legion of the empire and help from the Franks destroyed the Visigoth state for the last time. The Ostrogoth commander was given control of the new 'Kingdom of Aquitaine', which paid tribute to Byzantium.
The Franks, under Clovis had by then expanded their kingdom to include the territories of the Thuringians and the Alemanni. This secured his kingdom as a powerful one, and it would staydominant for the next few hundred years. Clovis himself converted to Christianity, a form much closer to the form the Byzantines used than the Arian form most barbarians converted to. This was considered heretical by the leaders of the Byzantine Church at that time. It would later evolve into what is called the Francian Church.
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