The Western Roman Empire was in steep delince by the 5th century AD and with this started the new historical age for Italy. The last centuries of the Western Empire encompass what is known as Late Antiquity but the later centuries after the fall of Rome are often known as the Dark Ages. The ways of the Roman Empire would continue in the East, but Italy would now be occupied by the barbarian tribes like the Goths and Lombards.
Alaric I of the Goths famously sacked Rome in 410, the city would never fully recover. Romulus Augustus, also known as Augustulus was the last Roman Emperor in the West and was deposed in 476 Germanic general Odoacer. Odoacer actually was already ruling Italy, with Romulus Augustulus as a puppet Emperor and later by himself for more than seventeen years under the title of rex gentium.
Thoedorcic the Great became king of Ostrogoths on February 25, 493 after defeating Odoacer. Theodric's reign was nearly a continuation of the old Roman ways with the fact is that he ruled Italy with the help of his Roman staff. The period of Theodric saw many improvements take place such as fixing the infrastructure, expansion of the frontiers and a strong economy. However this period of prosperity did not live much longer than Theodoric himself as weaker Goth rulers followed.
Sixth and Seventh Centuries
The beginning of the 6th century saw the return of the Eastern Roman Empire as the Emperor Justinian sought to regain the lost lands in the West. From the capital in Constantinople, Justinian sent his generals, Narses and Belisarius to conquer Italy. They succeeded in destroying the Kingdom of the Ostragoths in 552, after years of fighting. However these so-called Gothic Wars laid waste to much of Italy, with famine, disease and warfare nearly wiping out Italian town life.
Towns did not completely vanish, however the towns during the Dark Age were significantly smaller and much more primitave compared to the Late Roman times. Italy as a whole was becoming more rural, with agriculture the main occupation for most of the local population.
After the Gothic Wars, the Byzantine forces in Italy were not strong enough to defend against a new wave of invasion from the Lombards. The Lombards quickly carved out a kingdom for themselves, their rulers wearing the famous Iron Crown of Lombardy. The Byzantines were reduced to the coastal areas, most famously the Exarchate of Ravenna, while the Lombards would eventually spread even to Southern Italy.
In the wake of all this destruction and uncertainty, it was the church who stepped in to take a greater authority over Italy. Not only did the Catholic Church hold spiritual power, but the need for learned men for administration ensured a greater temporal power as well. The Bishop of Rome, the Pope has gained supremacy over the other religious leaders by this time and began to become a ruler in his own right, especially once the Byzantine Emperor's forces could no longer protect Italy from these new threats.
Eighth CenturyBy the middle of the eighth century, the Lombards had taken over Byzantine Ravenna and the Pope was in need of protection. The Lombards were a threat to the Pope since many were still pagan and the majority of Christian Lombards were Arian Christians, not Catholic. The Church looked for help among another Germanic tribe known as the Franks, who were also Catholic Christians. The Pope bestowed upon the Carolingians the spiritual authority to overthrow their weak Merovingian rulers in exchange for protection from the Lombards. After defeating the Lombards in 756, the Frankish King gave to the Pope the so-called Donation of Pepin, which created the Church ruled kingdom of the Papal States. The new Papal States separated what was left of the Italian Lombard lands in the North and South.
In 774 the Frankish ruler Charlemagne got the support from the Pope to invade Italy and annex the Lombard lands of Northern Italy. Shortly after this, Charlemagne was crowned as the first Holy Roman Emperor on December 25, 800 by the Pope. However this caused a problem with the Byzantines, who still considered themselves the real Roman Empire and still had possesions in Southern Italy. A brief war was settled in 812 with the Byzantines acknowledging the Holy Roman Empire so long as Byzantines lands in Italy remain uncontested.
Ninth and Tenth Centuries
Under the rule of Charlemagne, Northern Italy was under years of relative peace and rebirth, part of what is known as the Carolingian Renaissance. As major military and political events were taking place on the fringes of the Empire, Italy was able to recoup a bit from the previous centuries of invasion and strife. However the South was already seeing the emergence of raids by Arabs and the golden age of Charlemagne would not survive the Emperor's death.
The Empire was divided in three parts by the treaty of Verdun in 843, after the death of Charlemagne's son Louis the Pious. The Central Frankish realm was ruled by Emperor Lothair I, Northern Italy became the Kingdom of Italy ruled by Louis II, who became Emperor in 855.
After the creation of the Holy Roman Empire and the Papal States, Southern Italy consisted of the remaining two Lombard territories of Beneveto and Spoleto, which accepted Charlemagne's suzerainty only nominally. These Lombard lands would eventually declare defacto independence and would also start the Beneventan civil war until Emperor Louis II imposed his will and separated the entities. The Byzantine Empire still had a few possesions on the coasts but cities like Naples, Gaeta, Naples, Amalfi and Venice were gradually becoming free from Byzantium's influence. At this same time Amalfi and Venice began to prosper due to an increase in trade, especially salt and silks. Sea trade was revived and Italian merchants were trading with the major Mediterranean ports.
The early years of the 9th century witnessed the conquest of Sicily by Muslim Arabs who were known as Aghlabids. The island was a Byzantine possesion, but could not be heavily defended and so the invaders would take Palermo in 831 and eventually occupy the entire island. However, the Muslim threat was not confined to the island of Sicily.
In 846 a Muslim force attacked Rome, even St. Peter's Basilica was not spared from looting. In response to this attack, Pope Leo IV began the Leonine walls in Vatican City, completed in the year 853. After the Saracens occupied Bari in 852 Emperor Louis II, Adelchis of Benevento and the Byzantines announced a joint operation against Arabs in Southern Italy, succeeding in recapturing Bari, but Adelchis imprisoned Emperor Louis in a power play for independence. The Byzantines did make territorial gains in Southern Italy during this time, but were offset by the loss of Sicily by 902.
The thrones of Germany and Italy were united in 951 with the crowning of Otto I as Holy Roman Emperor in 962 and he claimed that union would revive the empire of Charlemagne. The Byzantine Empire created the Catepanate of Italy in order to administer the newly acquired region of Southern Italy. The other Italian cities of Southern Italy still remained divided among the Lombard kings, but paid nominal allegience to the Byzantine Emperor.