Alaric was the first King of the Visigoths and is most well-known for leading the sack of Rome in 410.

Details of his early life are sketchy. What is far more well-known is his life once he is a military commander. Born into a noble tribe of Goths, he fought under the banner of Rome in the late 4th Century, including helping Theodosius I defeat the usurper Arbogast at the Battle of River Frigidus in 394.

Theodosius, a co-emperor who ruled in the East, achieved the throne of the West as well, in 395, defeating all challengers to his rule. However, he also died in that year and left his sons as co-emperors, one in the West and one in the East. The sons were young, in Honorius's case very young, and a general named Flavius Stilicho acted as regent.

Part of the agreement that Theodosius had forged with the Gothic tribes was that they would be able to settle within the boundaries of the Empire as long as they agreed to provide soldiers to fight for the Empire. What the Visigoths discovered at the Battle of River Frigidus is that some Roman commanders were fond of putting the Goths on the front lines, absorbing many of the casualties so that troops from Rome proper could live to fight another day. Also, the agreement forged by Theodosius didn't include citizenship for the Goths living within the Empire. With those sore spots as an impetus, Alaric, named King of the Visigoths, set about trying to gain some advantage for his people. Choosing violence as a means of making Rome take notice, Alaric and the Visigoths moved into the Balkans and into Greece, ransacking cities as they went. They entered Italy in 402 and demanded grain and citizenship. Stilicho, leading the Roman military response, refused on both counts. The two armies clashed at Verona, and the Romans emerged victorious. In 406, however, the two commanders forged a plan to work together for mutual benefit. Stilicho, who was the real power in the West thanks to his daughter's marrying the Western emperor, Honorius, wanted to take control in the East, where Arcadius reigned. Alaric agreed to aid Stilicho in his efforts provided that the Visigoths' demands were met: grain, citizenship, and a new one, 4,000 pounds of gold.

At this time, a trio of other threats confronted Stilicho's ambitions. Radagaisus, a Gothic king, had chosen that moment to invade Italy; at the same time, the Alans, Survi, and Vandals had invaded Gaul; and Constantine III had put down a threat in Britain and looked like he had intentions on seizing overall power. Alaric, hearing nothing more from Stilicho and fearing that he'd been double-crossed, moved further toward Rome. It was at this point the Roman Senate refused to pay the gold that Alaric had requested. A Senator named Olympius, who thought that Rome's money would be better spent equipping its own armies for defending the realm, went with the emperor Honorius to Ticinum, south of Milan, and signed off on a massacre of thousands of Gothic soldiers who were ostensibly allies of Rome. For good measure, Olympius then ordered the execution of Stilicho, on the grounds of plotting with the enemy. An incensed Alaric vowed to punish Rome. He found himself with a host of new allies, as more than 10,000 Goths turned on the Romans, sacking Aquilea, Ariminum, Bononia, Concordia, Cremona, and Picenum (but bypassing Ravenna, the relatively newly named capital of the Western Empire.

Alaric and his army surrounded Rome, blocking all gates and preventing reinforcements of food, supplies, or weapons from coming via the River Tiber. Honorius, meanwhile, stayed in Ravenna, believing that Rome would never fall. Once the situation became dire, the Senate scraped together a combination of gold, silver, silk, and spices and sent them out to Alaric as an appeasement. Honorius, meanwhile, sent a force of Roman soldiers to confront the Visigoths surrounding Rome. Alaric made more attempts to avoid bloodshed, but nothing more was forthcoming from within the Eternal City. On August 24, 410, he gave the order to enter the city.