March 2, 537. A panicked cry alerts the guards of a once-great city, who quickly raise the gate. Pursued by his foes - the Goths of King Witiges - the small cavalry escort of Belisarius, General of the Byzantine Empire, retreats back within the walls of the great city that has been their goal for months. The Great Siege of Rome has begun.
The fall of Rome to mercenary Germans in 476 A.D. is traditionally dated as the end of the Roman Empire. In a sense, it was. France, Britain, Spain, North Africa, and Italy had fallen to Germanic or Gothic Kings, and the capture of the great city itself seemed to be a death blow to the Empire of the Romans.
Yet all was not as it seemed. The fall of Rome only heralded the end of the Western Roman Empire. The Eastern Roman Empire, centered on the great city of Constantinople, still possessed huge territories: Greece, the Balkans, Egypt, Syria, Palestine, and modern-day Turkey. It was surviving - even thriving. And as the Emperors in the East watched their kinsman's lands fall to barbarian hordes, most of them shook their heads in dismay, for they knew there was little they could do
The Emperor Justinian was not most Eastern Roman Emperors. A peasant soldier risen to power, whose wife Theodora was a famous prostitute and borderline genius, he was determined to start a new age of glory for the Romans. (They still called themselves Romans, even though they no longer held the Seven Hills of their predecessors.) Justinian amassed an enormous treasury, built a powerful army, and decided it was time to retake the lost territories.
He had a great general to accomplish this. Belisarius was a wunderkind commander, capable of performing extraordinary feats with few men. Justinian put this to the test. In 530 in modern Iraq, Belisarius smashed a Persian invasion force at Dara while outnumbered two to one. In 533, Justinian sent Belisarius to reconquer Africa (modern Tunisia) with a force of only 17,000 men, a tiny force in comparison to the enemy but again - Belisarius prevailed, returning the granaries of Africa to Roman authority.
Justinian, though, had his eyes set on the old capital itself. Rome. Once the seat of mighty glory, it had languished during the late Empire, and fared even worse under barbarian authority. Though its glories were faded, its aura still rang out across the Mediterranean. Justinian ordered Belisarius to prepare an invasion of Italy, which was currently ruled by the Goths. Belisarius, performing ridiculous feats with his small army, captured Sicily in 535 and Naples in 536, making his way towards the prize like a rock climber handhold by handhold. With the Gothic army not yet assembled, King Witiges fled the city; Belisarius's small army of 5,000 men took Rome on December 9, 536. After 60 years, Rome once again belonged to the Romans.
It wouldn't be that easy. The Gothic army had assembled in northern Italy, and it numbered over 40,000 men. Witiges was hellbent on expelling the Romans, and steamed south at full speed. Belisarius learned of this advance, and began to prepare Rome for a siege. He ordered its crumbling walls strengthened, citizens trained to fight, food stockpiled. Nevertheless, he was almost caught off guard when the Goths advanced quicker than he expected. Surprised by a Gothic raiding party, Belisarius barely escaped with his life on March 2, 537. That was the day the Siege began.
The Goths planned to starve out the Romans, establishing a loose ring around the city since they didn't have enough troops to surround it completely. Then they tried to break in. For every trick the Goths tried, Belisarius had a response. The Goths tried to move siege towers to the walls pulled by oxen; Belisarius had his best archers kill the oxen, leaving the towers useless. The Goths attempted to storm the city again; Belisarius led out sally parties to destroy their other siege engines. He also whittled down Gothic forces by using his cavalry as bait to draw them into the fire of ballistas and catapults. Nevertheless, Rome was starving, and Belisarius needed reinforcements.
Justinian sent a trickle of troops to help, even as Belisarius drove off attack after attack and faced an increasingly restive and discontent population within the walls. Many blamed Belisarius for bringing this upon them. Finally, another 5,000 men arrived in November to reinforce Belisarius, easily passing through the thin enemy cordon, and he began to prepare for an attack.
Even though he was still heavily outnumbered - 10,000 to 40,000 - the Roman general began to seize key points around the city that had the effect of cutting off the Goths from their own supplies. Gradually, the besiegers became the besieged. Finally, a detached Roman force seized the key Italian city of Rimini to the northeast, from which all Witiges' supplies ran. The Goths were forced to abandon the siege, and on March 12, 538, after 374 days, the Siege of Rome was lifted.
The Siege of Rome was the critical point in the Roman reconquest of Italy. By 540, Belisarius had forced the final submission of the Goths. Justinian could justifiably claim that he had, at least in part, reunified the Roman Empire through his great general and great army.
It was not to last. The fact that the Romans could only send such a small army to accomplish their triumphs was a signal that they did not have the resources to hold their new lands, even if they could take them under a great general. Within ten years, the Goths would make a comeback and retake Rome, forcing Belisarius to return to Italy and campaign against them again. Later in the 540s, a great plague - the so-called "Plague of Justinian" - would consume the Mediterranean, depleting the Roman economy and population so much that it had no hope of holding Italy long-term. The arrival of the Lombards in the 570s, after Justinian and Belisarius were both dead, signalled the final end to Roman rule in Italy.
In this way, Belisarius' victory at Rome actively proved a major problem for the Empire in the long term. The glimmer of success in Italy led the Emperors to pile resources into a land they could never hope to hold - the equivalent of a gambler's early success translating into dismal failure.
There were three major consequences of the last gasp of Roman power in Italy. First, the expenditure of resources and men trying to hold Italy led the Eastern Roman Empire to neglect the defense of its eastern provinces, which left them vulnerable first to the Persians and finally to the Muslim Arabs - with disastrous long-term consequences. Second, the failure of any outside political authority to maintain control of the city of Rome itself strengthened the position of its most notable resident, the Bishop of Rome. Due to his patriarchal status in Italy, he would soon be addressed simply as "father" - Papa. Or "Pope."
Finally, the ultimate failure to hold Rome caused the Eastern Romans to shed the final vestiges of the old Imperial system. The transformation started with Justinian, but in the next 100 years the language of the Empire would switch from Latin to Greek, its concerns would focus on Greece and Asia, and its Emperors increasingly assumed a spiritual and military status that Augustus, for instance, would have found utterly alien. The Eastern Romans still called themselves Roman, and they would until their final days - but to distinguish them from their very different predecessors, historians ever after have called them Byzantine.
Book Recommendation: For a brilliant look at Byzantine civilization, see Judith Herrin, Byzantium: The Surprising Life of a Medieval Empire (London: Allen Lane, 2007).