 In 387 BC he led an army of Cisalpine Gauls in their attack on Rome and captured most of the city, holding it for several months.Brennus's sack of Rome was the only time in 800 years the city was occupied by a non-Roman army before the fall of the city to the Visigoths in 410 AD.The Senones were a Gaulish tribe originating from the part of France at present known as Seine-et-Marne, Loiret, and Yonne, who had expanded to occupy northern Italy.