 Complete the following phrase:  Brennus or Brennos was a chieftain of the Senones. He defeated the Romans at the Battle of the Allia ca 390 BC. Later that year, he led an army of Cisalpine Gauls in their attack on Rome and captured most of the city, holding it for several months. Brennuss sack of Rome was the only time in 800 years the city was occupied by a non-Roman army before 