Rome fell to a foreign army in 410 AD for the first time in almost 800 years

In August 410, the Visigothic king Alaric led his army into Rome and sacked the city for three days. The last time Rome had fallen to an outside force was 390 BC, when Gauls overran it — nearly eight centuries earlier. Rome was no longer the empire's capital by then, but the shock rippled across the Mediterranean and is often marked as a turning point in the empire's decline.

— Alaric I, King of the Visigoths, Sack of Rome (410) — 24–27 August 410 CE