I’m going to let Gibbon set the stage.
“In the arts of negotiation, as well as in those of war, the Gothic king maintained his superior ascendant over an enemy, whose seeming changes proceeded from the total want of counsel and design. From his camp, on the confines of Italy, Alaric attentively observed the revolutions of the palace, watched the progress of faction and discontent, disguised the hostile aspect of a Barbarian invader.
The pressing invitation of the malcontents, who urged the king of the Goths to invade Italy, was enforced by a lively sense of his personal injuries; and he might especially complain, that the Imperial ministers still delayed and eluded the payment of the four thousand pounds of gold which had been granted by the Roman senate, either to reward his services, or to appease his fury. His decent firmness was supported by an artful moderation, which contributed to the success of his designs. He required a fair and reasonable satisfaction; but he gave the strongest assurances, that, as soon as he had obtained it, he would immediately retire.
The modesty of Alaric was interpreted, by the ministers of Ravenna, as a sure evidence of his weakness and fear. They disdained either to negotiate a treaty, or to assemble an army; and with a rash confidence, derived only from their ignorance of the extreme danger, irretrievably wasted the decisive moments of peace and war.
While they expected, in sullen silence, that the Barbarians would evacuate the confines of Italy, Alaric, with bold and rapid marches, passed the Alps and the Po; hastily pillaged the cities of Aquileia, Altinum, Concordia, and Cremona, which yielded to his arms; increased his forces by the accession of thirty thousand auxiliaries; and, without meeting a single enemy in the field, advanced as far as the edge of the morass which protected the impregnable residence of the emperor of the West. Instead of attempting the hopeless siege of Ravenna, the prudent leader of the Goths proceeded to Rimini, stretched his ravages along the sea-coast of the Hadriatic, and meditated the conquest of the ancient mistress of the world.
His troops, animated by the hopes of spoil, followed the course of the Flaminian way, occupied the unguarded passes of the Apennine, descended into the rich plains of Umbria… A lofty situation, and a seasonable tempest of thunder and lightning, preserved the little city of Narni; but the king of the Goths, despising the ignoble prey, still advanced with unabated vigor; and after he had passed through the stately arches, adorned with the spoils of Barbaric victories, he pitched his camp under the walls of Rome.”
Alaric initiated a siege against the city by blocking the twelve gates to prevent any communication outside the city. He also took control of the Tiber to prevent commerce from being conducted.
“The first emotions of the nobles, and of the people, were those of surprise and indignation, that a vile Barbarian should dare to insult the capital of the world: but their arrogance was soon humbled by misfortune…”
As food supplies ran out, the people of Rome began to understand the pain of famine. The daily allowance of three pounds of bread was eventually reduced to nothing.
“…the progress of famine invaded the marble palaces of the senators themselves. The persons of both sexes, who had been educated in the enjoyment of ease and luxury, discovered how little is requisite to supply the demands of nature; and lavished their unavailing treasures of gold and silver, to obtain the coarse and scanty sustenance which they would formerly have rejected with disdain.”
Thousands starved to death and bodies lay in the streets.
Finally, the senate, acting as the supreme power of the government, sent ambassadors to treat with the Gothic leader. Their approach was in keeping with their position.
“When they were introduced into his presence, they declared, perhaps in a more lofty style than became their abject condition, that the Romans were resolved to maintain their dignity, either in peace or war; and that, if Alaric refused them a fair and honorable capitulation, he might sound his trumpets, and prepare to give battle to an innumerable people, exercised in arms, and animated by despair.”
His famous reply was "The thicker the hay, the easier it is mowed," laughing at the gall of the Romans in their pitiable position. He set the ransom for breaking the siege at “all the gold and silver in the city, whether it were the property of the state, or of individuals; all the rich and precious movables; and all the slaves that could prove their title to the name of Barbarians”.
“The ministers of the senate presumed to ask, in a modest and suppliant tone, "If such, O king, are your demands, what do you intend to leave us?" "Your Lives!" replied the haughty conqueror: they trembled, and retired.
Yet, before they retired, a short suspension of arms was granted, which allowed some time for a more temperate negotiation. The stern features of Alaric were insensibly relaxed; he abated much of the rigor of his terms; and at length consented to raise the siege, on the immediate payment of five thousand pounds of gold, of thirty thousand pounds of silver, of four thousand robes of silk, of three thousand pieces of fine scarlet cloth, and of three thousand pounds weight of pepper.”
His terms were met in principle.
The gates were opened and the Roman people allowed to obtain the food they so severely required. Meanwhile the Goths moved north to set up winter quarters in Tuscany. But the administration in Ravenna did not trust Alaric, thinking he had some sinister purpose beyond their knowledge.
"Three senators, at his earnest request, were sent ambassadors to the court of Ravenna, to solicit the exchange of hostages, and the conclusion of the treaty; and the proposals, which he more clearly expressed during the course of the negotiations, could only inspire a doubt of his sincerity, as they might seem inadequate to the state of his fortune. The Barbarian still aspired to the rank of master-general of the armies of the West; he stipulated an annual subsidy of corn and money; and he chose the provinces of Dalmatia, Noricum, and Venetia, for the seat of his new kingdom, which would have commanded the important communication between Italy and the Danube.
If these modest terms should be rejected, Alaric showed a disposition to relinquish his pecuniary demands, and even to content himself with the possession of Noricum; an exhausted and impoverished country, perpetually exposed to the inroads of the Barbarians of Germany."
Amazingly, the chief minister of Honorius, Olympius, rejected the treaty and its alternatives. He ordered 6,000 troops to march from Ravenna to Rome to reinforce the city. This entire army was destroyed before it reached its destination.
"Yet Alaric, instead of resenting this act of impotent hostility, immediately renewed his proposals of peace; and the second embassy of the Roman senate, which derived weight and dignity from the presence of Innocent, bishop of the city, was guarded from the dangers of the road by a detachment of Gothic soldiers."
As a result of this calamity, Olympius was replaced by Jovius, the praetorian prefect. Initially, Jovius sought to craft a personal treaty with Alaric at Rimini. While he was away from Ravenna, Honorius drafted a letter negating the treaty. This missive fell into the hands of the King of the Goths.
“…the Goth, who in the whole transaction had behaved with temper and decency, expressed, in the most outrageous language, his lively sense of the insult so wantonly offered to his person and to his nation.
While the emperor and his court enjoyed, with sullen pride, the security of the marshes and fortifications of Ravenna, they abandoned Rome, almost without defense, to the resentment of Alaric. Yet such was the moderation which he still preserved, or affected, that, as he moved with his army along the Flaminian way, he successively dispatched the bishops of the towns of Italy to reiterate his offers of peace, and to congratulate the emperor, that he would save the city and its inhabitants from hostile fire, and the sword of the Barbarians.
These impending calamities were, however, averted, not indeed by the wisdom of Honorius, but by the prudence or humanity of the Gothic king; who employed a milder, though not less effectual, method of conquest. Instead of assaulting the capital, he successfully directed his efforts against the Port of Ostia, one of the boldest and most stupendous works of Roman magnificence.”
Alaric threatened an immediate attack on the grain silos of Ostia if the treaty was not completed immediately. At Ravenna, a usurper, named Attalus, was named as co-emperor in an attempt to take matters in a different direction. The gates of Rome were thrown open to him and he was conducted in a procession to the senate. He spoke to them about how the glory of Rome would be restored by his hand and sent envoys to measure of the loyalty of the provinces of Africa and Egypt.
Honorius, under threat of assassination from every quarter, was blessed with a stroke of luck when a ship landed at Ravenna with a reinforcing army. The envoys of Attalus had been killed by a loyal count of Africa who sent money and men to the emperor. Attalus was stripped of his office. Now Alaric arrived within three miles of Ravenna intent on including the long delayed treaty, but the handlers of Honorius could not see their way to an accommodation. They received a rival Barbarian chief, who killed many Goths during a foray from the city and proceeded to ridicule Alaric in a subsequent parade.
In a matter of a few days, the Gothic king and his army appeared at the gates of Rome intent on revenge for the many slights given him. A conspiracy forged with slaves inside the city facilitated the gates being opened to his army.
“The proclamation of Alaric, when he forced his entrance into a vanquished city, discovered, however, some regard for the laws of humanity and religion. He encouraged his troops boldly to seize the rewards of valor, and to enrich themselves with the spoils of a wealthy and effeminate people: but he exhorted them, at the same time, to spare the lives of the unresisting citizens, and to respect the churches of the apostles, St. Peter and St. Paul, as holy and inviolable sanctuaries.
In the sack of Rome, some rare and extraordinary examples of Barbarian virtue have been deservedly applauded. But the holy precincts of the Vatican, and the apostolic churches, could receive a very small proportion of the Roman people; many thousand warriors, more especially of the Huns, who served under the standard of Alaric, were strangers to the name, or at least to the faith, of Christ; and we may suspect, without any breach of charity or candor, that in the hour of savage license, when every passion was inflamed, and every restraint was removed, the precepts of the Gospel seldom influenced the behavior of the Gothic Christians. The writers, the best disposed to exaggerate their clemency, have freely confessed, that a cruel slaughter was made of the Romans; and that the streets of the city were filled with dead bodies, which remained without burial during the general consternation. The despair of the citizens was sometimes converted into fury: and whenever the Barbarians were provoked by opposition, they extended the promiscuous massacre to the feeble, the innocent, and the helpless.”
The Goths evacuated Rome on the sixth day. Weighted down by spoils, they proceeded south through Campania destroying everything in their path. Then, when Alaric reached Rhegium, he decided to cross to Sicily and see what he could find of value there. A crossing was arranged but a storm blew up during the passage that sank many ships. The plan was permanently abandoned when Alaric died unexpectedly.
The sack of Rome is a story of the pride of ages and its refusal to see reason. Oddly, it was the barbarian, Alaric, who was reasonable instead of the Romans. All he wanted for himself, and his people, was land within the empire that would protect them from the Huns. They respected what the Romans had accomplished and sought friendship and affiliation, but the Romans lacked the ability to see the world in its new form.